I learned alot from greg furnace . Clean it myself last year (great). This year cleaned it wasnt dirty, flushed lines no air , changed filter works like a charm. Thank you. You save me money!! And im a woman 62 years
I know this is an older video but I wanted to add that I had a similar valve and for about a year I would have to occasionally tap on that solenoid once I'd hear the click of the relay from the board which energized the line. Either it was weak or the plunger was sticking. So although the line was energized the valve was in fact bad. Unfortunately I was unable to find a vendor to sell just a solenoid so ultimately had to change the entire valve assembly. I've learned a lot over the years watching your video GFM. Thanks for taking the time to put them together.
Man gray, I have learned so freaking much from your videos! when i come upon a problem i go right to your page and 98% of the time i leave with the answer to the question and fix what i happen to be working on. Keep up the good work, wish i could have a apprenticeship with someone with all the knowledge that you have. thx again and keep the videos coming.
You saved me some time and money with this video. Had my AC replaced this summer and it appears the installers turned off the gas valve. Was able to tshoot it and turn it back on because of your video. Thanks a bunch for doing these.
This is one of the greatest real tech out there I admire. Thank you so much or your knowledge sharing, I learn a lot out of watching your videos. God bless you sir along with family.
you probably dont care but does any of you know a trick to get back into an Instagram account? I was dumb forgot the login password. I love any tips you can give me!
@Gannon Graysen thanks for your reply. I found the site on google and Im in the hacking process atm. I see it takes quite some time so I will get back to you later with my results.
Read the screen at "7" he corrected his statement, "As long as it's in line with the pipe it's off." He's a good teacher, watch and learn, and read the added boxes for further information. Thank you "grayfurnaceman" for your instructive videos. I'm sure in one of them, I'll come across my problem and you will show how to correct it.
I can't remember which video I commented on, and we discussed my furnace issue. Just wanted to give you an update from a couple weeks ago. My furnace wasn't producing any flame, and I ended up calling a technician in thinking I might need a new gas valve. Actually what had happened was that someone (a tech or previous homeowner) had installed a generic gas valve that wasn't meant for my furnace (A Rheem), but they got it to work. Well, the barb on the gas valve that received power was smaller than the clip attached to it......so in effect it was just loose. So basically a lose bit of wiring was the problem. The tech tightened it up with a pair of needle nosers. $95 gave me a little better piece of mind, even though the problem was just "that simple", haha.
More things to check in the same scenario. Are the burners or burner orifices clogged? Is there a blockage in the gas line itself? (very uncommon but can happen) Also, see if you can actually hear the gas valve clicking on. Lastly, if you verify voltage to the gas valve. Get a small hammer and give the side of the gas valve a wack (as its getting voltage input) This trick has helped me get someone heat many times. Beware if a gas valve sticks once. It will most likely happen again.
you are the man i havea mentor his name is kenny smith from newark nj iwork with him for manny manny year this guy has the patians like you i got cokie with him to manny times well any way i lost my job i realy enjoy this stuff you know and i enjoy working with ken he alway made en xtra effort to show me annything i know a lot thanks to my buddy smith i miss him and job i wach lot of your vidios for hours brother i only wish i had my hand on this tehcnalage years ago but u are the man keep up the good work my honest freind tony from newark
I like the way this furnace is wired. I think an On/Off Switch right on the side of the furnace is the way to go. Apparently this furnace is old enough that it doesn't suffer from a door safety switch.
I see some of the comments complain that this video is too long. Too many students yell "No theory..just tell me what's wrong!" Patience, Grasshopper.. Scannerdanner is another one who goes through all the steps (auto repair).
I have had some false readings with the 24v ones when there is a problem with the control board. But sometimes I still do use them. The way I did this is a more accurate test that not only tests whether there is voltage available, but that the part is actually energized. Thanks for the thoughts. GFM
The pilot orifice are often obstructed if it has been sitting awile, some units have a direct burner light off with no pilot assembly and tubing which your unit seems to be, the gas valves can get stuck physically, especially if no drip leg was installed.
the gas solenoid can be energizing, drawing current but still not open the valve. it may be stuck, putting your hand on the valve you can feel the valve movement or hear the click.
@@grayfurnaceman I don't have a gas flow meter. Do you think my gas valve is on its way out? This old 1980ish furnace has no circuit board just relays, transformer, ignitor, exhaust fan and a few more goodys.
@@grayfurnaceman I found a bad exhaust fan relay wasnt turning the exgaust fan on. Once it failed completely it was easier to find. Replaced it and back up and running.😀
Another good video thank you! A faulty IFC may still send a signal to the GV, but the voltage may be insufficient. But there will still be a amp draw and your test will lead you to a wrong conclusion. I always connect my DVM parallel to the GV and observe both, the quality and the timing of the signal. My tencents anyway.
My neighbor’s had a switch, set to off, behind a screwed down panel instead of removable. Brand new..I think they are taking advantage of her, she had already made an appointment for a service call..
I had to replace a gas hot water heater and turned off the gas to the house. I have three carrier furnace systems. The one most used cycles through but no flame. Gas is back on as the hot water heater 7' away is operating. This unit is the far side of the house from gas source. It was working before the turn off happened. Any suggestions?
Thanks for the great video series! Last week I found my igniter completely burnt up and the board was toasted too. Replaced both with new OEM White Rodgers parts. Furnace starts normally. Inducer comes on, igniter gets red hot but I get no flame. I am able to get it to light if I hold a lighter next to the burner. It seems like the igniter starts to cool off before the gas get released. Any thoughts?
i have an older Rheem is not an " inducer " style. ( with a new Mercury Flame sensor ) it has a spark ignition and that all seems fine, but it will light the pilot and will stay lit for about 1 minute or so than turns off ( and will continue to cycle like this. It just wont fire up. What do you think? Thank you
The mercury pilot switch has failed. Bad news is they are no longer available. Repair would require a complete changeover to an intermittent pilot system. It can be done but good luck finding a tech that would do it. GFM
Hi, I have an old fraser-johnston gas furnace (model#100CD42BNA) from I think 1972 (ser is C114572). Now there's gas leaking from around the OFF/PILOT/ON knob on the gas valve. Unfortunately, we haven't been able to find a replacement. Any ideas where or how to find a replacement valve for this old furnace to hold us through this season until we can buy a new system? Thanks and keep up the great videos
I have a nordyne furnace with Honeywell gas valve, the furnace will ignite and stay lit for 1-30 seconds then shut the gas valve. No trouble codes flashing on the board. It will eventually run a full heat cycle after many tries. Does this sound like a control board problem?
My furnace seems to be going through the entire sequence-of-operations correctly up to where the hot surface ignitor lights, and then I get 24-25 volts on the gas valve -- but I only get 24 volts for maybe one second, and the voltage drops back to zero -- before there is any ignition. It seems like maybe some (safety) check is failing and the voltage is being removed. How would I go about isolating this issue further, e.g., to the gas valve itself, or the control board, or...? I don't want to start randomly buying new parts w/o a better guess as to the root problem. Is there a video (or videos) that addresses this kind of symptom? Thanks for any help you can provide. Your videos are great.
I have a brand new Revolv90 80% the pre vent fan comes on and cycles. Then when the gas valve is energized the valve has a loud and hard knock or click noise 3 times then burner ignites. Any advice what should I look for???? Thanks Ive learned lots from your videos.
Working on a Lennox, trouble light is telling me that gas valve won't light because flame is already sensed. this is the new trouble after I have replaced the board, inducer and pressure switch...any thoughts?
Thanks for your videos. I have HSI lighting up, but no ignition. 24 volts and amp draw at gas valve. Replaced gas valve. New valve fired up furnace first time, now it won't start again. Error code on furnace says reverse polarity, which I have verified polarity is correct.
When I have had that condition, I found no amp draw at all. The Robertshaw 780 control would do that. It would show 13 to 16 volts but it was a ghost voltage and there was no real power going to the gas valve.I guess that's my ten cents. GFM
I have a 9 year old janitrol 80% forced air gas furnace. Ignitor comes on but gas isn't flowing (burner doesn't come on). If i tap on the electronic that sit on top of the gas valve, it will come on and the furnace will work. Sometimes it will work for an hour, sometimes 2 weeks. But sooner or later, i'll wake up cold. I'll restart the furnace with master power switch to start the startup cycle, ignitor comes on, tap on electronics box attached to gas valve, whoosh, and I'm good to go till next time. Just need about 4 taps to get it started.
I've seen the solenoids stick on gas valves to where a slight rap with your driver when the valve is energizing will unstick it. Normally not for long though. I would replace the valve. Some newer units have limit switches in series with the gas valve wiring. Check the wiring on any limit that is connected to the electrical wires running to your gas valve. Also check that the limit isn't opening. 4 years to late but maybe someone will get some help from this comment.
My friend has an old Coleman pilot light forced air natural gas heater in a double mobile home. I starts up and seems fine but the blower shuts down after about 3 minutes for a minute or two than cycles like that before the wall thermostat reach s set temperature, the fire still continues in the heater box.. It has 3 thermostats one on the blower, one near the to of the heater box and one near the bottom of the heat box. Any suggestions? Thank you
Or the fastest way would be hook your manometer to the outlet side of the valve then when you are watching for amp draw you can see if the valve opens or not
Videos are very informative. I do have a question about my furnace gas valve. My furnace every once in awhile does not turn on it does not send gas to ignite. I think the problems with the valve have checked wires I do have amp draw. But I have noticed when it doesn't work if I wiggle the wires at the gas valve and cycle again it works. Also if it is running and I wiggle the gas valve wires it shuts off. Have checked the wires they check fine. Is it possible the board or wires or pens inside the gas valve could be faulty?
Yes, could be bad wire connection in or out of the solenoid. Also, imagine the plunger in the solenoid is sticking. A solenoid is an electro-magnetic device. When power applied & connected through the solenoid, the coils in it create a strong magnetic force that pulls (or pushes) the plunger/ pin in, or out. Usually a weak spring will keep the pin in the closed position till energized.
I've spent over $1500 the heating companies always tell me its this or that but had the same issue for 2 years.When it gets cold out the heater always gives me issues I changed the flame sensor,the igniter,the mother board etc but never the gas control valve I have a feeling that will solve the mystery as every part has been changed except that and I just tested gas supply its perfect.Leaves me to think gas valve is the issue
@@grayfurnaceman it works when its day time almost always 90% of the time every night between say 2 am till 8 am its off wont turn on i have a basic thermostat no ability to add schedule.What happens is fan tuns on igniter gets hot glows then stops the process goes 3 times and then shuts down and turns off i then flip the switch it goes threw the same process over and over I cleaned the flame sensor i even cleaned the igniter I changed the filter and the battery in thermostat i also had the gas company check my gas coming into house also all other gas appliances work never any issues.I have a Lennox furnace.
@@Fm-ss4uj Your description of symptoms does indicate a gas valve failure. I would be looking at the wiring to the gas valve and power shown during a call for ignition. GFM
@@grayfurnaceman so I got 25.5 volts from gas valve but I put a candle lighter right by igniter it didn't turn on and I put my gas meter no gas coming out I think gas valve is stuck not allowing gas to flow properly I have to turn switch on and off and sometimes it turns on I just ordered a new gas valve last part to change.
I read that the gas valve on our Rheem model that was installed a week ago is prone to issues. Wondering if I can ask for a different model from the company that installed them instead? They only warranty it for a year and manufacturers 5 years. Paid $2800.
@@mikenowitzki6732 There should be a sticker on the valve with the model # on it. If you are asking about where the valve is, follow the gas piping going to the furnace. The aluminum box is the valve. GFM
HELP I have a Raheem Imperial 90 Plus furnace the pilot will not light The power works because the blower is running I’ve been working on it for hours my family is freezing What can I do to get it to work?
On 110 volt washing machines we would use a 110 volt clip chord to force water valves on to test if they are working. Is there a way to force the furnace valve on by connecting the solenoid to a 24 volt AC current supply? I believe you can also check the solenoid for continuity with an ohm meter. If it's open, it's dead.
You could use jumpers from R and C terminals of the control board to the terminals of the gas valve. This will bypass all safeties, so be aware. An ohmmeter will probably be useless as there is a rectifier in series with the solenoid. GFM
I have gas valve that wont shut off. when turning the valve from the off position to the pilot position it immediately starts hissing and releasing gas...without pushing the pilot button down. stuck open maybe? ive tried cycling the power with no luck. help is greatly appreciated.
I had similar problem. Once you see a Igniter RED hot and do not get gas to start fire then gently hit valve with screw driver rubber handle. Furnace fire started but stopped after few on/off cycles. After few repetitions I removed the valve connector and applied (little) anti-oxidation elect contact grease and put it back. After that It is running for more than three days. But I do not trust. So I will order a new gas valve and ask my HVAC tech buddy (we share lots of good technical information) to come and replace when he has a time. I am an elect.Engineer and worked on Industrial computer control designs for years and know that all technical persons have mastered some special skill. I never changed the furnace gas valve so let him change that. He is a HVAC tech and have changed gas valve many times.
HI, we have an old floor furnace, the pilot is strong but doesn't seem to react when I turn the wall thermostat on. How to fix? How do I check / get to ,the thermocouple/ pile? Can I pull it out of the floor by myself? or how heavy is it? I don't see any make or model # . I have 2 control handles poking up, what are they for? Thank you
I think if you decide to pull it up, I would replace it. It does have access from below. The control handles are probably temp control and the off-pilot-on switch. If the unit is in the on position, and the pilot is blue, and covering the thermopile, I would make sure all wiring connections are tight. GFM
Thank you for your reply. Just to let you know...i finally ran a jump from 24v trans to Gas v/v and wks fine. I thought ...could it be they sent me a dud used board. You think so too. Thx. One other thought - pin 7 on 9 pin plug has never had a flame sensor. Do you think the new used board is sencing this and bypasses the gas valve?
how about remove the cap on the service port and hook up you manifold? if you can get a reading after g.v energized, it means the solenoid inside of the g.v is good and vice versa.
Thanks for the great videos. Did all the checks and determined the gas valve was bad. Replaced it and it worked fine for an hour or 2. Same issue. No gas from valve. HSI fires, I get power to valve but I did notice it was at 90 volts for a split second then down to 25 volts or so for 4 seconds. Could my board be shorting out my valve? Thx
+grayfurnaceman Thanks so much for responding so quickly. I took the old valve and tested it a 24 volt transformer I had and it works fine. Thought I'd try to replace the HSI since it's Friday and then control which will have to be ordered. Your videos have been a great help!
+grayfurnaceman Updating for others. Replaced the control board and works like a charm. Had a sticking limit switch but all good now. Appreciate your very informative videos.
Thanks GFM! Can I share this with my study-buddies at school? We're in a gas fitter program in a community college in Toronto, Canada and I find your videos explain things in such a way that it supports what our teachers tell us and vice-versa. The truly neat thing is that we can always go back and look at your instruction again and again...
Thanks for video a little off topic but I see the Honeywell electronic cleaner I converted back to a standard filter never thought they worked very well what is your opinion thanks for all the videos
Dealing with a Carrier Infinity Package Unit. It will properly go through the ignition sequence, fire off, run through a cycle, but when the room temp reaches the temp to restart another heat cycle the unit will sometimes cycle again for a few cycles or it may not cycle again. If it fails, it will ignite three times but not sustain a burn then lockout for 3 hrs unless you reset the unit by turning the power off then back on to the unit. A 34 code will show, then a 14 after 3 firing attempts The flame sensor had been cleaned then a new one installed with the same result. I am leaning toward a faulty/weak gas valve solenoid. Any suggestions? Thanks!
Finally figured out the issue and maybe this will help someone else. It was not the board and not the flame sensor. We have two of these package units side by side, and they both were giving the same "34" error code which made me suspect that both boards and both flame sensors would not be causing the same issue at the same time. As I said, sometimes they would work ok, then go to error. The flame tubes are a little low to the ground, but I was on my hands and knees once when I fired it off. Only the tube with the ignitor was burning, and no flame traveled to the other tubes after ignition, hence the flame sensor never got involved in the sequence. My son and I pulled out the burner units, and the flame side edge of the burner had rusted enough that it impeded the gas flow across the front to the other burners. I cleaned up the rust, reinstalled the burner unit on both package units, and they have worked flawlessly since. Am in the process of getting new burners. We live in a high humidity area which probably contributed to the rust issue. Thanks for your time to respond. Kind of hard to diagnose things over the internet without getting hands on. Enjoy your videos.
@@grayfurnaceman thank you for your reply, it ended up being the IC inside the board that was damaged and had an on / off behavior with a code 7 on a Trane white Rodgers IFC. I used your video to troubleshoot the gas valve. Then I removed the board and diode checked back to the IC. Thank you.
MY furnace has been acting up for a few months now. At first the inducer was running while the stat was in AC mode. It would turn on randomly and turn off. thought the stat was bad so i changed it. Still had the random problem with the inducer then all the sudden the blower would run too. When I finally turned the furnace on it seemed fine. All the sudden it started doing the same thing.....the inducer and blower would run for no reason. 2 days ago I was laying in bed and heard it short cycling. Well last night after work I got home and hear it spinning up. The gas never came on and it shut off. Went and checked it and the inducer would run and the HSI would glow. When it was supposed to turn the gas on it would just shut off. I took the door panel off to stop this cycle because it would not stop. Pressed the switch and it spun up. This time it fired up and ran. released the switch and put the door on. it spun up and then would not fire. There were no fault codes on the board. Figured since the ignite would glow that my limit switch was fine and the pressure switch worked. Didn't think there could be a gas valve issue since i was having strange issues prior to this happening. I ended up ordering a control board. Hope this is my issue.
The blower motor will run if you power on the furnace while there's a call for heat (thermostat on). It's a safety measure. Turn the thermostat off before powering on unit. Sounds like you're experiencing the problem I addressed above.
Thanks for all your vids GFM, I'm learning a alot! Question, I went to look at a Coleman furnace Dgat056dbf at a mobile home. I checked the limit switch, flame sensor, gas valve was being energized, but whats happening is the igniter turns on flame is lit but as soon as the blower kicks in, it turns off! when it try's again it will light, and then turns off again. I replaced the flame sensor, and the board and also bypassed the limit switches to see if furnace would stay on.
Victor P The heat exchanger is a very difficult to replace part (and also is expensive.) Chances are, if the heat exchanger is bad, then the furnace should be replaced as a whole unless the heat exchanger is under warranty. It may be a flame rollout caused by a bad heat exchanger. Check the flames before the blower comes on and after the blower comes on to make sure they aren't rolling out. If they're rolling out, chances are you either have a bad heat exchanger or something is blocking the flue. The rollout sensor will detect a rollout and shut the furnace down for safety reasons. If it is rolling out the front, shut the furnace off and keep it off until you can replace the furnace or have a HVAC tech out to check the flue/heat exchanger. A blocked flue or cracked heat exchanger can release CO into the home which can be deadly. If something is blocking the flue, typically the pressure switch will not close and the furnace won't attempt to light - so it sounds like you may possibly have a bad heat exchanger. Coleman used to have drum heat exchanger (GFM made a video one a Coleman CGU with a drum heat exchanger) and those are really difficult to inspect. A typical furnace heat exchanger (clamshell or tubular design) are easier to inspect, especially on an up flow furnace, as you can run a camera through down through the evaporator coil casing or through the blower compartment (if it is an 80% furnace) to look for holes, cracks, or missing rivets. Hopefully you can figure out what is the problem - probably best to leave it up to an HVAC tech who better knows what they're looking for.
Hello, the heater cycle begins, igniter lights gas valve comes on and three of the four burners fire except the one with the cleaned flame sensor and that happen to be the non-lighting tube. If I blow on the other flames it will carry over and light. I took a fine pick and put it in the gas jet just to make sure a spider or skunk was not clogging it:) What could it be??? POWER WAS OFF...
First, clean the burners. Check the manifold pressure and set to factory specs. You could also check the heat exchanger for cracks and flame rollout from a cracked heat exchanger. Hope this helps. GFM
What if the gas valve is stuck and you put amp meter on it and its showing amp draw. Your saying if you have amp draw the gas valve is good and its a gas supply problem. I am wondering if im not understanding what you are saying in this video? Thanks for posting this.
You might want to watch the video again. I may not have been as clear as I could have been. This video was done as a simple way to determine if the gas valve was energizing. The determination of gas flow is a separate issue. GFM
We have a Concord 92G1 series furnace, it's, 4 years old. It was acting odd by turning on but, not blowing any warm air. Repair guy said it's the main gas valve. Then an hour later it started working fine, and has been for, 3 days now. If it's the main valve, would the valve work intermittently, like that? Thanks...
Thanks very much, gfm. My husband thinks it may have had a tiny piece of dirt or, a spider in it, when it was tapped with a wrench, it cleared, it out. Possible??? Thanks, so very much.
The turning on was probably just the inducer motor during startup. The solenoid on top of the valve loses strength over time and will have trouble pulling the plunger so a light tap often works. Mine gave me trouble over the last 5 yrs intermittently so I kept a little wood stick to tap it right after I'd hear the click that energizes it. Tried to order new solenoid but aren't available as a separate part so finally changed out the valve ($116). An amp test like shown here should indicate if the coil (solenoid) is losing strength by higher than normal draw. The gas valve should have the proper amps listed on it. You'll need a manometer to adjust the gas pressure after replacing valve available onlne for about $30 (digital).
The way to confirm is to check manifold gas pressure. If you have amp draw but no gas pressure, there's no gas. If you have inlet pressure as well, the gas valve is bad.
hi there, i have the same furnace as in your video but my furnace is not doing anything, and i mean anything. I've rebooted it as outlined in the instruction on the panel and nothing happened. it just makes a very low volume buzz. i also have a gas fireplace which won't ignite past the pilot light. i had the gas company Technician come and check and he said the pressure in the line was good and it must be the 2 devices that failed at the same time. after tapping the controls on the fireplace, he got the thing to light up but when i went back to it, it was back to pilot light only. i had to keep tapping it every 2 minutes to get it to work. i don't use the fireplace much but I've never experienced this kind of behavior from it before. I've checked my thermostat, filter, main fuse panel, intake and exhaust pipes and everything altars to be OK. could you please give me an idea of what i should check before i call someone to take a $100 from me for tapping something on the furnace. Greatly appreciate your help.
+Rishabh Bhatia The fireplace is probably not indicative of a gas supply problem. Check the blinking code of the furnace. There is key for what the codes mean either on the inside of one of the panels or on the control board. Hope this helps. GFM
+grayfurnaceman Thanks for the reply. I have called a repair guy to come check it out. I also found some brown colored dust/residue which might indicate a water intrusion into the blower motor, although I'm not sure how. Will have to wait for him to see what needs to be done.
I have a gas furnace that works intermittently but I wanted your opinion on something. I moved into this house earlier this year and at the time the furnace seemed to be working fine for those couple months. I had a company come out to clean the furnace and they recommended replacing the surface ignitor and the flame sensor which they did. When we went to turn the furnace on last month it started being intermittent. Basically, inducer motor comes on, 30 seconds or so later the surface ignitor comes on, then the gas will either ignite or it wont. Sometimes when it does ignite it will turn off after a few seconds. I always get code 34, flame proving failed. I had a tech come out to look at it and they said the inlet pressure was good but the outlet was intermittent. He recommends replacing the gas valve for 493 bucks, which I did not do. Anyways, is there any possibility that there could be another problem besides the gas valve causing this, say intermittent voltage to the valve? How can I check that, is it constant 24v or only when the surface ignitor is on? Is that AC or DC? Don't know if I want to invest another 500 into this furnace at this point it's about 10 years old.
So once you determine that there is voltage going to your GV but no gas, would you then check manifold pressure? and if everything is good do you then simply replace the gas valve??
+Johnathan Briggs I would check manifold pressure. No pressure, check for incoming pressure. Pressure in, no pressure out gas valve failure. Hope this helps. GFM
If the unit has been running normally and has lately started kicking the rollout, I would be looking for a cracked heat exchanger. Change in flame when the fan comes on is a dead giveaway. GFM
I am not really sure the about the letters on the valve. Probably for manufacturer use. Teflon tape is sometimes used, but I have found it is not a good thread seal. Hope this helps. GFM
Having a prob on an old gas furnace where the u light the pilot light it stays on but when I turn the heater on the blower comes on but I'm guessing the gas is not flowing through the chambers. What could be the problem?
If the inducer cycles, ignitor comes on, the gas valve clicks (24v verified), this says all the pressure switches and sensors are working -correct? The flame sensor circuit is not even active yet -correct? Bad flame sensors will only show up after flame should be detected -correct? I have all of the above, with no flame. Additionally I have a modulating gas valve (97% furnace) with an additional stepper motor in the valve that is not turning (took the cover off and made an inspection hole to observe the stepper shaft end). Bad Valve? Board? or something else? Yes, I paid my bill, and there is presence of gas at the valve and other appliances work. Thanks.
So, I had a local heating company with a good reputation give me an estimate of the repair. He checked exactly what I checked and also guessed that it is the valve. He had no idea why the stepper was not turning and could not ascertain that the signal to it was correct, meaning the board may have not been sending it the correct control signal, due to an internal logic problem or a distressed signal from elsewhere (this valve has 24v power and Tx, Rx wiring). When asked if replacing a good component was on his dime, he said it was not. I will not call him again. I thank you for the reply and admire what you do for this audience. I also understand that a company's proprietary information sometimes protects the contractor and the consumer. But in the real world there are many many similar circumstances involving MUCH more liability than a furnace. Some devices are better kept in the 'black box' department and some people have to be told to call a professional, but this is a furnace, it's not rocket science -it's not even science. I am kind of horrified that proper diagnostic procedures are not more readily available with the bit of new electronics that some of these have -it will get worse -probably much worse -things tend to get more complicated, but maybe better? There might be an app for that! A good portion of my work is in life support equipment, mostly mechanical. When a system is working or not, you are supplied by the manufacturer with comprehensive information to read the process of the devise, for failure prevention, and when and if it is failing, the problem is overly thought through, so you thoroughly understand the problem, the symptoms, peripherals, the result and the fix. I see very little of this happening in this industry. So, I tried what you did in another video -manually lighting -I got just a flicker and movement on the outside regulator/meter, banged on the mod valve after it induced, glowed and clicked, got a little more -and eventually got full operation (not a fix I'm proud of). I had taken the valve apart previously, but didn't get into the stepper section since it was absolutely clean -was just checking for corrosion/blockage -that's a large screen! I will buy a valve, install and check the pressures, but I can't help but think think a diaphragm/spring kit or a bit of lube wouldn't get it back online for the rest of this furnaces life. Here's a dumb question -are rebuild kits available? Don't laugh, they are for every devise I work on. thanks again.
One of the reasons there are no parts for those valves is the liability issue you brought up. Even if the manual valve knob on the gas valve is not replaceable as the breaking of the knob indicates the valve is failing. If you give met the manufacturer and model # I may have service info that may help. GFM
@@salvor1 Hello 6 years later, my friend. I hope you are well. The problem that you are having is echoed by dozens of posters in these comments, none of which having satisfactory resolution. Your comparison to medical devices is very insightful because these machines in northern climates indeed decide who might suffer injury to people or their property so it is imperative to have full transparency. But there is none. A 30-cent grommet is held hostage for a $300 inducer assembly while all of the talking heads are screaming at the plebes to conserve and go-green. A 30-cent edge connector is sold as a side harness for $63 when they know that their poor design will burn them out. What we are looking at can be said no other way: Krim In All. If the gas valves are indeed bad then I think I have identified one of the reasons that the suppliers to the end users ship them in oversized boxes with no packing material so that they are tumbled in the dryer (so to speak) halfway across the nation before they get to the end user already defective. LOTS of repeat business from that. If you have resolved your problem please post again to tell us what you find because this problem is systemic to the very few mega-corporations that make multiple brand names that all use the same or similar defective parts and system. Thanks. GFM caught me into his channel when I first saw his video on the scam of cracked heat exchangers. Diogenes would be pleased.
My inducer kicks on, air switch closes, ignitor glows, then 27 volts get sent through wires to valve, but no gas. I'm replacing valve tomorrow, I feel it has to be bad? I have confirmed I have gas in pipe upstream from valve. Thanks
First, be sure gas is available, then I would check amp draw of the gas valve when it is energized. Sometimes the control will only send a ghost voltage with no amperage. GFM
Hi. Tried replacement valve today (used). Still no gas. Confirmed I have gas upstream from valve. Then I followed your advice and checked both valves for amp draw and it says its drawing amps the whole time, but like .06. Doesnt change after ignitor glows. Sound like bad valve? Thank you.
My furnace is letting a rare scent fume when it is on. I just had a shimney sweap because I thought that was the reason for the smell I was getting. Nevertheless, the fumes are still there. It doesn't smell like gas but some type of combustion. Please guide me.
It is probably burnt gas. If its a natural draft furnace(older than 25 years), it is probably not venting properly or there is a crack in the heat exchanger. This needs to be looked into. There is a possibility of CO poisoning. Your best bet is to get a service tech out there. Hope this helps. GFM
Valve 36G24 205 made a hissing noise and only one burner out of three came on.(one closest to HSI) Then with no flame sense it goes out. I allow it only to retry once. Circuit board blinks normal green. Stove/oven works fine. After eight years could my gas valve be dying? Of course it is Sunday and it is snowing. The sub. seems to be 36J24 214. Thank You!
Not the gas valve it's obviously opening that's the hissing your hearing!! Take out each individual brass orfices and clear them something is stopping the gas from making it to the other burners
Ivan Luis The hiss is an entirely new sound from listening to it for eight years. A soft tapping on the diaphram side and it works again now. But I an still considering changing it unless I find something else.
grayfurnaceman Can you as an expert tell me if these valves can partially fail? Meaning are there ever failures where the valve only opens part of the way? Perhaps the regulator, which is built in, failed? I clean the furnace every fall but it has run for years without failing even once. And the heat exchanger is some kind of titanium alloy, which I imagine accounts for the hefty unconditional warranty. It is a Dayton(York)I do service work too and it drives me crazy not seeing the end result of a weird problem so I will keep you informed.
Thanks for the great video. My gas valve is not getting any current to it at all. So where do i go from here? Does that mean it needs to be or is there a problem with the power source?
Adrian Loera Remember, the gas valve is only energized for 4 to 7 seconds during a trial for ignition. It should have power after the HSI warms up. GFM
Adrian Loera I assume you do not show voltage at the gas valve at any time. If so, its not the gas valve. Its kind of like running out of gas in your car. You don't replace the car, you put gas in it. Now, If the furnace is less than 25 years old, It probably uses a hot surface ignitor to ignite the gas. Is it coming on? GFM
Adrian Loera did you solve the problem? i have a similar problem now if i unplug the flame senser i will turn the gas on but if i dont put the plug back on quickly then it will shut off
My gas valve is not getting power. I’ve changed the board thinking for sure that would be the issue, as no power is being sent to the valve. The transformer has correct power going to the board. Any thoughts?
The control board will not allow a trial for ignition until the conditions are right. The pressure switch must be proved open, the inducer must prove the venting has no restrictions, the HSI must prove its on, when the gas valve opens, flame must be proved or it shuts down within 4 to 7 seconds. Any break in the sequence and the sequence stops. What are the symptoms? GFM
grayfurnaceman About a 7 year old Lennox unit. Everything cycles as it should. Fan comes on. Igniter glows. As the relay clicks in the board to send power to gas valve, it all shuts down. I’ve got two units in the attic. Swapped vacuum switch off my working unit to the non working, still nothing. Last thought was the gas valve after board did not work. So I got a 24v source, hooked up to the gas valve (which was disconnected) and it opened. Since I did that though, now the board pops the fuse every time it tries to open the valve...
@@williamsoape7220 If you have not miswired the valve, I have to say the valve is shorted. I know you tested it, but there is nothing else that I can think of. GFM
grayfurnaceman For some reason I never checked the ohms on the valve. It’s at around 330. Valve on the other furnace is almost 1k. Wasted money on the board I think
I have a Rheem furnace. I put a used board in because my previous direct spark board would not spark reliably ... intermittently. I had to tap the board to get it to send a spark, then it would engage the gas valve and run fine for a week or so. Now back to where I'm at now....the used board I put in looks very similar. All wires are transferred correctly. The sequence goes; inducer fan, vacuum switch, direct sparks, then blower just blows cold air. I am going to chk the gas valve for amps like you said but I am wondering if it's this board as it's not exactly the same as the original. Is it needing something else to function? It's a 62-24136-01. I tried a ICM 292 board. It did exactly the same sequence. If I put the original back in, the gas valve works fine but maybe just for a week. Any clues as to what's going on?
Mr. GFM, thank you for all your support; greatly appreciated.
I learned alot from greg furnace . Clean it myself last year (great). This year cleaned it wasnt dirty, flushed lines no air , changed filter works like a charm. Thank you. You save me money!! And im a woman 62 years
Glad you got it done. I would love to more women using my videos. About 90% of my viewers are men.
GFM
Im a licensed tech & want to say thank you, needed a few refreshments.
Gray don't listen to people you do a great job and you very detailed which is good. You take as much time as you need
I know this is an older video but I wanted to add that I had a similar valve and for about a year I would have to occasionally tap on that solenoid once I'd hear the click of the relay from the board which energized the line. Either it was weak or the plunger was sticking. So although the line was energized the valve was in fact bad. Unfortunately I was unable to find a vendor to sell just a solenoid so ultimately had to change the entire valve assembly. I've learned a lot over the years watching your video GFM. Thanks for taking the time to put them together.
Welcome
GFM
Man gray, I have learned so freaking much from your videos! when i come upon a problem i go right to your page and 98% of the time i leave with the answer to the question and fix what i happen to be working on. Keep up the good work, wish i could have a apprenticeship with someone with all the knowledge that you have. thx again and keep the videos coming.
Glad I can make a difference.
GFM
grayfurnaceman
Thanks for the support and I will keep them coming.
GFM
You saved me some time and money with this video. Had my AC replaced this summer and it appears the installers turned off the gas valve. Was able to tshoot it and turn it back on because of your video. Thanks a bunch for doing these.
This is one of the greatest real tech out there I admire. Thank you so much or your knowledge sharing, I learn a lot out of watching your videos.
God bless you sir along with family.
Josue Castillo Thanks for the support.
GFM
you probably dont care but does any of you know a trick to get back into an Instagram account?
I was dumb forgot the login password. I love any tips you can give me!
@Sutton Quinton Instablaster :)
@Gannon Graysen thanks for your reply. I found the site on google and Im in the hacking process atm.
I see it takes quite some time so I will get back to you later with my results.
@Gannon Graysen It worked and I actually got access to my account again. Im so happy:D
Thanks so much, you saved my account :D
Read the screen at "7" he corrected his statement, "As long as it's in line with the pipe it's off." He's a good teacher, watch and learn, and read the added boxes for further information.
Thank you "grayfurnaceman" for your instructive videos. I'm sure in one of them, I'll come across my problem and you will show how to correct it.
I can't remember which video I commented on, and we discussed my furnace issue. Just wanted to give you an update from a couple weeks ago. My furnace wasn't producing any flame, and I ended up calling a technician in thinking I might need a new gas valve. Actually what had happened was that someone (a tech or previous homeowner) had installed a generic gas valve that wasn't meant for my furnace (A Rheem), but they got it to work. Well, the barb on the gas valve that received power was smaller than the clip attached to it......so in effect it was just loose. So basically a lose bit of wiring was the problem. The tech tightened it up with a pair of needle nosers. $95 gave me a little better piece of mind, even though the problem was just "that simple", haha.
+StormLaker1975 Thanks for the reply. Glad its working.
GFM
.
Well...made it all the way through winter, she's working as good as ever. Now to have a guy come out and do the annual service on our Central Air:-)
More things to check in the same scenario.
Are the burners or burner orifices clogged?
Is there a blockage in the gas line itself? (very uncommon but can happen)
Also, see if you can actually hear the gas valve clicking on.
Lastly, if you verify voltage to the gas valve. Get a small hammer and give the side of the gas valve a wack (as its getting voltage input)
This trick has helped me get someone heat many times. Beware if a gas valve sticks once. It will most likely happen again.
Thanks to your video I was able to find a wire touching the igniter that had melted. Thank you very much
I bet you could do an awesome kermit the frog impersonation
Wow
if Kermit was retarded
The roach dude on men & black 😂
😂
you are the man i havea mentor his name is kenny smith from newark nj iwork with him for manny manny year this guy has the patians like you i got cokie with him to manny times well any way i lost my job i realy enjoy this stuff you know and i enjoy working with ken he alway made en xtra effort to show me annything i know a lot thanks to my buddy smith i miss him and job i wach lot of your vidios for hours brother i only wish i had my hand on this tehcnalage years ago but u are the man keep up the good work my honest freind tony from newark
+Tony Laracuente Thanks for the support.
GFM
I like the way this furnace is wired. I think an On/Off Switch right on the side of the furnace is the way to go. Apparently this furnace is old enough that it doesn't suffer from a door safety switch.
I see some of the comments complain that this video is too long. Too many students yell "No theory..just tell me what's wrong!" Patience, Grasshopper.. Scannerdanner is another one who goes through all the steps (auto repair).
Most of my videos do this or are separated into 2 parts. You need to teach for the one that the one that takes the most time to understand.
GFM
Almost always yes. The amp draw will be almost non existent if the voltage is low or it will chatter. Thanks for the thoughts.
GFM
Q lol ll
Doohickey haven't heard that since I was a kid . Great video
I have had some false readings with the 24v ones when there is a problem with the control board. But sometimes I still do use them. The way I did this is a more accurate test that not only tests whether there is voltage available, but that the part is actually energized. Thanks for the thoughts.
GFM
You are awesome, thanks so much. I've learned so much about furnace repair from your videos!
Merry Christmas
GFM
On Bryant 2 stage furnaces it fires in second stage first for a few seconds then drops into first stage.
The pilot orifice are often obstructed if it has been sitting awile, some units have a direct burner light off with no pilot assembly and tubing which your unit seems to be, the gas valves can get stuck physically, especially if no drip leg was installed.
thanks for the video Mr. furnaceman. i appreciate your videos
the gas solenoid can be energizing, drawing current but still not open the valve. it may be stuck, putting your hand on the valve you can feel the valve movement or hear the click.
Thanks for the video Grayfurnace!
I can wiggle the wires at my gas valve and it will light and may work for days or it might not work all day.
Dump the valve.
GFM
@@grayfurnaceman I don't have a gas flow meter.
Do you think my gas valve is on its way out?
This old 1980ish furnace has no circuit board just relays, transformer, ignitor, exhaust fan and a few more goodys.
@@grayfurnaceman I found a bad exhaust fan relay wasnt turning the exgaust fan on.
Once it failed completely it was easier to find.
Replaced it and back up and running.😀
Any way you get there, we all get to the same place. Thanks for the thoughts.
GFM
GREAT VIDEO !!! Although this is LONG, but it's worth it !!!
Glad it helped.
GFM
"Did you pay your bill?"....hilarious.
But true.
GFM
that was a fast fix. haha. thanks for the video grayfurnaceman. subscribing.
That's too funny 🤣.
Another good video thank you! A faulty IFC may still send a signal to the GV, but the voltage may be insufficient. But there will still be a amp draw and your test will lead you to a wrong conclusion. I always connect my DVM parallel to the GV and observe both, the quality and the timing of the signal. My tencents anyway.
UA-cam saves the day once again! Thanks sir, very helpful.
Welcome
GFM
You are right. Should be "on". Thanks for the heads up.
GFM
My neighbor’s had a switch, set to off, behind a screwed down panel instead of removable. Brand new..I think they are taking advantage of her, she had already made an appointment for a service call..
If you have pics, I may be able to help.
GFM
I had to replace a gas hot water heater and turned off the gas to the house. I have three carrier furnace systems. The one most used cycles through but no flame. Gas is back on as the hot water heater 7' away is operating. This unit is the far side of the house from gas source. It was working before the turn off happened. Any suggestions?
Excellent presentation. Keep up the good work.
Thanks for the great video series! Last week I found my igniter completely burnt up and the board was toasted too. Replaced both with new OEM White Rodgers parts. Furnace starts normally. Inducer comes on, igniter gets red hot but I get no flame. I am able to get it to light if I hold a lighter next to the burner. It seems like the igniter starts to cool off before the gas get released. Any thoughts?
+Nathan Todd This one could be placement of the hot surface ignitor or dirty burners. Hope this helps.
GFM
i have an older Rheem is not an " inducer " style. ( with a new Mercury Flame sensor ) it has a spark ignition and that all seems fine, but it will light the pilot and will stay lit for about 1 minute or so than turns off ( and will continue to cycle like this. It just wont fire up. What do you think? Thank you
The mercury pilot switch has failed. Bad news is they are no longer available. Repair would require a complete changeover to an intermittent pilot system. It can be done but good luck finding a tech that would do it.
GFM
Hi, I have an old fraser-johnston gas furnace (model#100CD42BNA) from I think 1972 (ser is C114572). Now there's gas leaking from around the OFF/PILOT/ON knob on the gas valve. Unfortunately, we haven't been able to find a replacement. Any ideas where or how to find a replacement valve for this old furnace to hold us through this season until we can buy a new system? Thanks and keep up the great videos
I don't believe this furnace needs anything special. A standing pilot gas valve such as the White Rodgers 3603-300 should work well.
GFM
@@grayfurnaceman Thanks for your expertise and your time getting back to me.
I heard if the gas off/on switch is parallel with the pipe is was ON not off, is that right?
I have a nordyne furnace with Honeywell gas valve, the furnace will ignite and stay lit for 1-30 seconds then shut the gas valve. No trouble codes flashing on the board. It will eventually run a full heat cycle after many tries. Does this sound like a control board problem?
Sounds like a flame rod problem. Cleaning it with sandpaper may help[.
GFM
My furnace seems to be going through the entire sequence-of-operations correctly up to where the hot surface ignitor lights, and then I get 24-25 volts on the gas valve -- but I only get 24 volts for maybe one second, and the voltage drops back to zero -- before there is any ignition. It seems like maybe some (safety) check is failing and the voltage is being removed. How would I go about isolating this issue further, e.g., to the gas valve itself, or the control board, or...? I don't want to start randomly buying new parts w/o a better guess as to the root problem. Is there a video (or videos) that addresses this kind of symptom? Thanks for any help you can provide. Your videos are great.
Some of the control boards sense if the gas valve is using power and if not, it shuts down. There should be a blinking code.
GFM
I have a brand new Revolv90 80% the pre vent fan comes on and cycles. Then when the gas valve is energized the valve has a loud and hard knock or click noise 3 times then burner ignites. Any advice what should I look for???? Thanks Ive learned lots from your videos.
Working on a Lennox, trouble light is telling me that gas valve won't light because flame is already sensed. this is the new trouble after I have replaced the board, inducer and pressure switch...any thoughts?
GFM do you encourage tech's to use the 120v & 24v pocket tick safety checkers, for checking for voltages in this instance?
Thanks for your videos. I have HSI lighting up, but no ignition. 24 volts and amp draw at gas valve. Replaced gas valve. New valve fired up furnace first time, now it won't start again. Error code on furnace says reverse polarity, which I have verified polarity is correct.
Sometimes, when a board fails, it will indicate reverse polarity.
GFM
When I have had that condition, I found no amp draw at all. The Robertshaw 780 control would do that. It would show 13 to 16 volts but it was a ghost voltage and there was no real power going to the gas valve.I guess that's my ten cents.
GFM
Gray, love your videos.. have you ever made a low volt test light for eliminating ghost voltages?
I have a 9 year old janitrol 80% forced air gas furnace. Ignitor comes on but gas isn't flowing (burner doesn't come on). If i tap on the electronic that sit on top of the gas valve, it will come on and the furnace will work. Sometimes it will work for an hour, sometimes 2 weeks. But sooner or later, i'll wake up cold. I'll restart the furnace with master power switch to start the startup cycle, ignitor comes on, tap on electronics box attached to gas valve, whoosh, and I'm good to go till next time. Just need about 4 taps to get it started.
Looks like a gas replacement to me. You might make sure the terminals on the valve are tight. Hope this helps.
GFM
I've seen the solenoids stick on gas valves to where a slight rap with your driver when the valve is energizing will unstick it. Normally not for long though. I would replace the valve.
Some newer units have limit switches in series with the gas valve wiring. Check the wiring on any limit that is connected to the electrical wires running to your gas valve. Also check that the limit isn't opening. 4 years to late but maybe someone will get some help from this comment.
Peinados faciles
My friend has an old Coleman pilot light forced air natural gas heater in a double mobile home. I starts up and seems fine but the blower shuts down after about 3 minutes for a minute or two than cycles like that before the wall thermostat reach s set temperature, the fire still continues in the heater box.. It has 3 thermostats one on the blower, one near the to of the heater box and one near the bottom of the heat box. Any suggestions? Thank you
You are probably moving too much air through the furnace. You can try lowering the blower speed.
GFM
Or the fastest way would be hook your manometer to the outlet side of the valve then when you are watching for amp draw you can see if the valve opens or not
Videos are very informative. I do have a question about my furnace gas valve. My furnace every once in awhile does not turn on it does not send gas to ignite. I think the problems with the valve have checked wires I do have amp draw. But I have noticed when it doesn't work if I wiggle the wires at the gas valve and cycle again it works. Also if it is running and I wiggle the gas valve wires it shuts off. Have checked the wires they check fine. Is it possible the board or wires or pens inside the gas valve could be faulty?
Yes, could be bad wire connection in or out of the solenoid. Also, imagine the plunger in the solenoid is sticking.
A solenoid is an electro-magnetic device.
When power applied & connected through the solenoid, the coils in it create a strong magnetic force that pulls (or pushes) the plunger/ pin in, or out. Usually a weak spring will keep the pin in the closed position till energized.
I've spent over $1500 the heating companies always tell me its this or that but had the same issue for 2 years.When it gets cold out the heater always gives me issues I changed the flame sensor,the igniter,the mother board etc but never the gas control valve I have a feeling that will solve the mystery as every part has been changed except that and I just tested gas supply its perfect.Leaves me to think gas valve is the issue
There is really nothing I can say to help without knowing the symptoms.
GFM
@@grayfurnaceman it works when its day time almost always 90% of the time every night between say 2 am till 8 am its off wont turn on i have a basic thermostat no ability to add schedule.What happens is fan tuns on igniter gets hot glows then stops the process goes 3 times and then shuts down and turns off i then flip the switch it goes threw the same process over and over I cleaned the flame sensor i even cleaned the igniter I changed the filter and the battery in thermostat i also had the gas company check my gas coming into house also all other gas appliances work never any issues.I have a Lennox furnace.
@@Fm-ss4uj Your description of symptoms does indicate a gas valve failure. I would be looking at the wiring to the gas valve and power shown during a call for ignition.
GFM
@@grayfurnaceman thanks for the info I have spent enough to nearly buy a new furnace so far thats the only part left
@@grayfurnaceman so I got 25.5 volts from gas valve but I put a candle lighter right by igniter it didn't turn on and I put my gas meter no gas coming out I think gas valve is stuck not allowing gas to flow properly I have to turn switch on and off and sometimes it turns on I just ordered a new gas valve last part to change.
Thanks for the support.
GFM
I read that the gas valve on our Rheem model that was installed a week ago is prone to issues. Wondering if I can ask for a different model from the company that installed them instead? They only warranty it for a year and manufacturers 5 years. Paid $2800.
Can you give me a model of the valve? Not the furnace, the valve.
GFM
@@grayfurnaceman appreciate the reply. Where is it located?
@@mikenowitzki6732 There should be a sticker on the valve with the model # on it. If you are asking about where the valve is, follow the gas piping going to the furnace. The aluminum box is the valve.
GFM
HELP
I have a Raheem Imperial 90 Plus furnace the pilot will not light
The power works because the blower is running
I’ve been working on it for hours my family is freezing
What can I do to get it to work?
On 110 volt washing machines we would use a 110 volt clip chord to force water valves on to test if they are working. Is there a way to force the furnace valve on by connecting the solenoid to a 24 volt AC current supply? I believe you can also check the solenoid for continuity with an ohm meter. If it's open, it's dead.
You could use jumpers from R and C terminals of the control board to the terminals of the gas valve. This will bypass all safeties, so be aware. An ohmmeter will probably be useless as there is a rectifier in series with the solenoid.
GFM
@@grayfurnaceman What about clamping the white? Would that show Amperage? It's allegedly active for both high and low fire.
@@grayfurnaceman Good to know about using R and C as a power source for 24 volt devices.
I have gas valve that wont shut off. when turning the valve from the off position to the pilot position it immediately starts hissing and releasing gas...without pushing the pilot button down. stuck open maybe? ive tried cycling the power with no luck. help is greatly appreciated.
Yep its dead. Get rid of it before there is a fire.
GFM
I had similar problem. Once you see a Igniter RED hot and do not get gas to start fire then gently hit valve with screw driver rubber handle. Furnace fire started but stopped after few on/off cycles. After few repetitions I removed the valve connector and applied (little) anti-oxidation elect contact grease and put it back. After that It is running for more than three days. But I do not trust. So I will order a new gas valve and ask my HVAC tech buddy (we share lots of good technical information) to come and replace when he has a time. I am an elect.Engineer and worked on Industrial computer control designs for years and know that all technical persons have mastered some special skill. I never changed the furnace gas valve so let him change that. He is a HVAC tech and have changed gas valve many times.
I'm only getting .007 to .009 amps. It sounds like it's clicking. Can debris make it stick?
THANK YOU, THANK YOU AND THANK YOU all it was is a loose harness on the valve again thank you
Glad you got it going.
GFM
Elias Georgakopoulos
HI, we have an old floor furnace, the pilot is strong but doesn't seem to react when I turn the wall thermostat on. How to fix? How do I check / get to ,the thermocouple/ pile? Can I pull it out of the floor by myself? or how heavy is it? I don't see any make or model # . I have 2 control handles poking up, what are they for? Thank you
I think if you decide to pull it up, I would replace it. It does have access from below. The control handles are probably temp control and the off-pilot-on switch. If the unit is in the on position, and the pilot is blue, and covering the thermopile, I would make sure all wiring connections are tight.
GFM
Looks like this just checks if power is going to the gas valve itself -- NOT a check if the gas valve itself is working -- is that correct?
Thank you for your reply. Just to let you know...i finally ran a jump from 24v trans to Gas v/v and wks fine. I thought ...could it be they sent me a dud used board. You think so too. Thx.
One other thought - pin 7 on 9 pin plug has never had a flame sensor. Do you think the new used board is sencing this and bypasses the gas valve?
+DIY FIX GUY I can't tell you on that one.
GFM
how about remove the cap on the service port and hook up you manifold? if you can get a reading after g.v energized, it means the solenoid inside of the g.v is good and vice versa.
That will work if there is a port on the outlet side of the valve.
GFM
Thanks Man I'm a newer HVAC Tech trying to build up my skills.
Congrats. Its a great profession.
GFM
Thanks for the great videos. Did all the checks and determined the gas valve was bad. Replaced it and it worked fine for an hour or 2. Same issue. No gas from valve. HSI fires, I get power to valve but I did notice it was at 90 volts for a split second then down to 25 volts or so for 4 seconds. Could my board be shorting out my valve? Thx
+Stuart Wright I have not seen it but it could be. Sounds like a new control.
GFM
+grayfurnaceman Thanks so much for responding so quickly. I took the old valve and tested it a 24 volt transformer I had and it works fine. Thought I'd try to replace the HSI since it's Friday and then control which will have to be ordered. Your videos have been a great help!
+grayfurnaceman Updating for others. Replaced the control board and works like a charm. Had a sticking limit switch but all good now. Appreciate your very informative videos.
Thanks for the support
GFM
Thanks GFM! Can I share this with my study-buddies at school? We're in a gas fitter program in a community college in Toronto, Canada and I find your videos explain things in such a way that it supports what our teachers tell us and vice-versa. The truly neat thing is that we can always go back and look at your instruction again and again...
I'm in Toronto and need someone to come look furnace!! Can you help
Had same problem the other day. Igniter lit no ignition. Come to find out my propane regulator froze up.
If I remove the wires from the gas valve, should I test the voltage on the terminals of the gas valve or the wires themselves? Thank you.
Test where the power comes from, not the load. Test the wires.
GFM
@@grayfurnaceman Thank you so much.
Thanks for video a little off topic but I see the Honeywell electronic cleaner I converted back to a standard filter never thought they worked very well what is your opinion thanks for all the videos
It actually works well.
GFM
Dealing with a Carrier Infinity Package Unit. It will properly go through the ignition sequence, fire off, run through a cycle, but when the room temp reaches the temp to restart another heat cycle the unit will sometimes cycle again for a few cycles or it may not cycle again. If it fails, it will ignite three times but not sustain a burn then lockout for 3 hrs unless you reset the unit by turning the power off then back on to the unit. A 34 code will show, then a 14 after 3 firing attempts The flame sensor had been cleaned then a new one installed with the same result. I am leaning toward a faulty/weak gas valve solenoid. Any suggestions? Thanks!
If the burner flame is covering the flame rod, you probably have a control board problem.
GFM
Finally figured out the issue and maybe this will help someone else. It was not the board and not the flame sensor. We have two of these package units side by side, and they both were giving the same "34" error code which made me suspect that both boards and both flame sensors would not be causing the same issue at the same time. As I said, sometimes they would work ok, then go to error. The flame tubes are a little low to the ground, but I was on my hands and knees once when I fired it off. Only the tube with the ignitor was burning, and no flame traveled to the other tubes after ignition, hence the flame sensor never got involved in the sequence. My son and I pulled out the burner units, and the flame side edge of the burner had rusted enough that it impeded the gas flow across the front to the other burners. I cleaned up the rust, reinstalled the burner unit on both package units, and they have worked flawlessly since. Am in the process of getting new burners. We live in a high humidity area which probably contributed to the rust issue. Thanks for your time to respond. Kind of hard to diagnose things over the internet without getting hands on. Enjoy your videos.
Thank you for sharing your experience with us. Can a valve be intermittently working ?
It certainly can. Not real common but it does happen.
GFM
@@grayfurnaceman thank you for your reply, it ended up being the IC inside the board that was damaged and had an on / off behavior with a code 7 on a Trane white Rodgers IFC. I used your video to troubleshoot the gas valve. Then I removed the board and diode checked back to the IC. Thank you.
Welcome
GFM
Good video. You could have a blocked jet causing ignition failure. I had that on my furnace.
Would that gas valve be 24 volts? If so doing a amp test will indicate that it is getting voltage, but is it getting the full 24 volts to it.
Thanks for the tips you have provided here.
MY furnace has been acting up for a few months now. At first the inducer was running while the stat was in AC mode. It would turn on randomly and turn off. thought the stat was bad so i changed it. Still had the random problem with the inducer then all the sudden the blower would run too.
When I finally turned the furnace on it seemed fine. All the sudden it started doing the same thing.....the inducer and blower would run for no reason. 2 days ago I was laying in bed and heard it short cycling. Well last night after work I got home and hear it spinning up. The gas never came on and it shut off. Went and checked it and the inducer would run and the HSI would glow. When it was supposed to turn the gas on it would just shut off. I took the door panel off to stop this cycle because it would not stop. Pressed the switch and it spun up. This time it fired up and ran. released the switch and put the door on. it spun up and then would not fire. There were no fault codes on the board.
Figured since the ignite would glow that my limit switch was fine and the pressure switch worked. Didn't think there could be a gas valve issue since i was having strange issues prior to this happening. I ended up ordering a control board. Hope this is my issue.
did that fix it?
im having similar issue.
The blower motor will run if you power on the furnace while there's a call for heat (thermostat on). It's a safety measure. Turn the thermostat off before powering on unit. Sounds like you're experiencing the problem I addressed above.
Thanks for all your vids GFM, I'm learning a alot! Question, I went to look at a Coleman furnace Dgat056dbf at a mobile home. I checked the limit switch, flame sensor, gas valve was being energized, but whats happening is the igniter turns on flame is lit but as soon as the blower kicks in, it turns off! when it try's again it will light, and then turns off again. I replaced the flame sensor, and the board and also bypassed the limit switches to see if furnace would stay on.
Victor P Have you checked the heat exchanger?
GFM
I have not. is the Heat exchanger a replaceable part?
Victor P The heat exchanger is a very difficult to replace part (and also is expensive.) Chances are, if the heat exchanger is bad, then the furnace should be replaced as a whole unless the heat exchanger is under warranty. It may be a flame rollout caused by a bad heat exchanger. Check the flames before the blower comes on and after the blower comes on to make sure they aren't rolling out. If they're rolling out, chances are you either have a bad heat exchanger or something is blocking the flue. The rollout sensor will detect a rollout and shut the furnace down for safety reasons. If it is rolling out the front, shut the furnace off and keep it off until you can replace the furnace or have a HVAC tech out to check the flue/heat exchanger. A blocked flue or cracked heat exchanger can release CO into the home which can be deadly. If something is blocking the flue, typically the pressure switch will not close and the furnace won't attempt to light - so it sounds like you may possibly have a bad heat exchanger. Coleman used to have drum heat exchanger (GFM made a video one a Coleman CGU with a drum heat exchanger) and those are really difficult to inspect. A typical furnace heat exchanger (clamshell or tubular design) are easier to inspect, especially on an up flow furnace, as you can run a camera through down through the evaporator coil casing or through the blower compartment (if it is an 80% furnace) to look for holes, cracks, or missing rivets. Hopefully you can figure out what is the problem - probably best to leave it up to an HVAC tech who better knows what they're looking for.
1912RamblerFan01 thank you for letting me know.
Hello, the heater cycle begins, igniter lights gas valve comes on and three of the four burners fire except the one with the cleaned flame sensor and that happen to be the non-lighting tube. If I blow on the other flames it will carry over and light. I took a fine pick and put it in the gas jet just to make sure a spider or skunk was not clogging it:)
What could it be??? POWER WAS OFF...
First, clean the burners. Check the manifold pressure and set to factory specs. You could also check the heat exchanger for cracks and flame rollout from a cracked heat exchanger. Hope this helps.
GFM
Gary,
I swapped it with another tube and the pilot flame lit all burners.
Thanks
Merry Christmas
GFM
What if the gas valve is stuck and you put amp meter on it and its showing amp draw. Your saying if you have amp draw the gas valve is good and its a gas supply problem. I am wondering if im not understanding what you are saying in this video? Thanks for posting this.
I was thinking the same thing if their is an amp draw than wouldn't that mean the gas valve is bad?
You might want to watch the video again. I may not have been as clear as I could have been. This video was done as a simple way to determine if the gas valve was energizing. The determination of gas flow is a separate issue.
GFM
@ACentertainmentCo if the gas is on then it was a problem with the valve.
Jumping in here.
Kermit the frog retired from sesame Street and started working for the gas company
We have a Concord 92G1 series furnace, it's, 4 years old. It was acting odd by turning on but, not blowing any warm air. Repair guy said it's the main gas valve. Then an hour later it started working fine, and has been for, 3 days now. If it's the main valve, would the valve work intermittently, like that? Thanks...
It could be intermittent. It would be unusual but it has happened.
GFM
Thanks very much, gfm. My husband thinks it may have had a tiny piece of dirt or, a spider in it, when it was tapped with a wrench, it cleared, it out. Possible??? Thanks, so very much.
Possible but not probable.
GFM
grayfurnaceman, thank you, once again. You've been super, helpful.
The turning on was probably just the inducer motor during startup. The solenoid on top of the valve loses strength over time and will have trouble pulling the plunger so a light tap often works. Mine gave me trouble over the last 5 yrs intermittently so I kept a little wood stick to tap it right after I'd hear the click that energizes it. Tried to order new solenoid but aren't available as a separate part so finally changed out the valve ($116). An amp test like shown here should indicate if the coil (solenoid) is losing strength by higher than normal draw. The gas valve should have the proper amps listed on it. You'll need a manometer to adjust the gas pressure after replacing valve available onlne for about $30 (digital).
The way to confirm is to check manifold gas pressure. If you have amp draw but no gas pressure, there's no gas. If you have inlet pressure as well, the gas valve is bad.
hi there, i have the same furnace as in your video but my furnace is not doing anything, and i mean anything. I've rebooted it as outlined in the instruction on the panel and nothing happened. it just makes a very low volume buzz. i also have a gas fireplace which won't ignite past the pilot light. i had the gas company Technician come and check and he said the pressure in the line was good and it must be the 2 devices that failed at the same time. after tapping the controls on the fireplace, he got the thing to light up but when i went back to it, it was back to pilot light only. i had to keep tapping it every 2 minutes to get it to work. i don't use the fireplace much but I've never experienced this kind of behavior from it before. I've checked my thermostat, filter, main fuse panel, intake and exhaust pipes and everything altars to be OK. could you please give me an idea of what i should check before i call someone to take a $100 from me for tapping something on the furnace. Greatly appreciate your help.
+Rishabh Bhatia The fireplace is probably not indicative of a gas supply problem. Check the blinking code of the furnace. There is key for what the codes mean either on the inside of one of the panels or on the control board. Hope this helps.
GFM
+grayfurnaceman Thanks for the reply. I have called a repair guy to come check it out. I also found some brown colored dust/residue which might indicate a water intrusion into the blower motor, although I'm not sure how. Will have to wait for him to see what needs to be done.
I have a gas furnace that works intermittently but I wanted your opinion on something. I moved into this house earlier this year and at the time the furnace seemed to be working fine for those couple months. I had a company come out to clean the furnace and they recommended replacing the surface ignitor and the flame sensor which they did.
When we went to turn the furnace on last month it started being intermittent. Basically, inducer motor comes on, 30 seconds or so later the surface ignitor comes on, then the gas will either ignite or it wont. Sometimes when it does ignite it will turn off after a few seconds. I always get code 34, flame proving failed.
I had a tech come out to look at it and they said the inlet pressure was good but the outlet was intermittent. He recommends replacing the gas valve for 493 bucks, which I did not do. Anyways, is there any possibility that there could be another problem besides the gas valve causing this, say intermittent voltage to the valve? How can I check that, is it constant 24v or only when the surface ignitor is on? Is that AC or DC?
Don't know if I want to invest another 500 into this furnace at this point it's about 10 years old.
+Warped3k You could have a failing gas valve, wiring problem between the board and the valve or the board could be failing. Hope this helps.
GFM
+Warped3k I had the same problem. It was just a wiring connection. Might be worth getting a second opinion?
StormLaker1975
So once you determine that there is voltage going to your GV but no gas, would you then check manifold pressure? and if everything is good do you then simply replace the gas valve??
+Johnathan Briggs I would check manifold pressure. No pressure, check for incoming pressure. Pressure in, no pressure out gas valve failure. Hope this helps.
GFM
Flame roll out switch keeps kicking off. I've noticed what looks like a low gas flow or the heat exchanger is bad. Can it be the solenoid?
If the unit has been running normally and has lately started kicking the rollout, I would be looking for a cracked heat exchanger. Change in flame when the fan comes on is a dead giveaway.
GFM
2 questions? What do the letters on the gas valve R--DV mean? Is it ok to use Teflon tape on the gas pipe threads or just pipe dope? Thanks.
I am not really sure the about the letters on the valve. Probably for manufacturer use. Teflon tape is sometimes used, but I have found it is not a good thread seal. Hope this helps.
GFM
But what if you don't have a clamp meter and just have a multimeter?
Having a prob on an old gas furnace where the u light the pilot light it stays on but when I turn the heater on the blower comes on but I'm guessing the gas is not flowing through the chambers. What could be the problem?
If there is power to the gas valve and all valves are open, the gas valve has failed. Hope this helps.
GFM
If the inducer cycles, ignitor comes on, the gas valve clicks (24v verified), this
says all the pressure switches and sensors are working -correct? The
flame sensor circuit is not even active yet -correct? Bad flame sensors
will only show up after flame should be detected -correct? I have all
of the above, with no flame. Additionally I have a modulating gas valve
(97% furnace) with an additional stepper motor in the valve that is not
turning (took the cover off and made an inspection hole to observe the
stepper shaft end). Bad Valve? Board? or something else? Yes, I paid my bill,
and there is presence of gas at the valve and other appliances work. Thanks.
You are correct about the sequence. If gas is available, and power is to the gas valve and no flame comes on, I would suspect the valve.
GFM
So, I had a local heating company with a good reputation give me an estimate of the repair. He checked exactly what I checked and also guessed that it is the valve. He had no idea why the stepper was not turning and could not ascertain that the signal to it was correct, meaning the board may have not been sending it the correct control signal, due to an internal logic problem or a distressed signal from elsewhere (this valve has 24v power and Tx, Rx wiring). When asked if replacing a good component was on his dime, he said it was not. I will not call him again.
I thank you for the reply and admire what you do for this audience. I also understand that a company's proprietary information sometimes protects the contractor and the consumer. But in the real world
there are many many similar circumstances involving MUCH more liability than a furnace. Some devices are better kept in the 'black box' department and some people have to be told to call a professional, but this is a furnace, it's not rocket science -it's not even science. I am kind of horrified that proper diagnostic procedures are not more readily available with the bit of new electronics that some of these have -it will get worse -probably much worse -things tend to get more complicated, but maybe better? There might be an app for that!
A good portion of my work is in life support equipment, mostly mechanical. When a system is working or not, you are supplied by the manufacturer with comprehensive information to read the process of the devise, for failure prevention, and when and if it is failing, the problem is overly thought through, so you thoroughly understand the problem, the symptoms, peripherals, the result and the fix. I see very little of this happening in this industry.
So, I tried what you did in another video -manually lighting -I got just a flicker and movement on the outside regulator/meter, banged on the mod valve after it induced, glowed and clicked, got a little more -and eventually got full operation (not a fix I'm proud of). I had taken the valve apart previously, but didn't get into the stepper section since it was absolutely clean -was just checking for corrosion/blockage -that's a large screen! I will buy a valve, install and check the pressures, but I can't help but think think a diaphragm/spring kit or a bit of lube wouldn't get it back online for the rest of this furnaces life.
Here's a dumb question -are rebuild kits available? Don't laugh, they are for every devise I work on.
thanks again.
One of the reasons there are no parts for those valves is the liability issue you brought up. Even if the manual valve knob on the gas valve is not replaceable as the breaking of the knob indicates the valve is failing. If you give met the manufacturer and model # I may have service info that may help.
GFM
@@salvor1 Hello 6 years later, my friend. I hope you are well. The problem that you are having is echoed by dozens of posters in these comments, none of which having satisfactory resolution. Your comparison to medical devices is very insightful because these machines in northern climates indeed decide who might suffer injury to people or their property so it is imperative to have full transparency. But there is none. A 30-cent grommet is held hostage for a $300 inducer assembly while all of the talking heads are screaming at the plebes to conserve and go-green. A 30-cent edge connector is sold as a side harness for $63 when they know that their poor design will burn them out. What we are looking at can be said no other way: Krim In All.
If the gas valves are indeed bad then I think I have identified one of the reasons that the suppliers to the end users ship them in oversized boxes with no packing material so that they are tumbled in the dryer (so to speak) halfway across the nation before they get to the end user already defective. LOTS of repeat business from that.
If you have resolved your problem please post again to tell us what you find because this problem is systemic to the very few mega-corporations that make multiple brand names that all use the same or similar defective parts and system. Thanks.
GFM caught me into his channel when I first saw his video on the scam of cracked heat exchangers. Diogenes would be pleased.
Thank you for the video. I will try it out.. Funny thing is that now its working like a charm..
at 702 did he say, if it's in line with the gas it's OFF? I don't think so, that means it's ON
I did say it was off. Note the text on the right side of the video correcting myself. Or did you use ad blocking software?
GFM
grayfurnaceman it doesn't show if you're using ad blocking software. I didn't see it either but I knew what you meant. Thanks for the video.
My inducer kicks on, air switch closes, ignitor glows, then 27 volts get sent through wires to valve, but no gas. I'm replacing valve tomorrow, I feel it has to be bad? I have confirmed I have gas in pipe upstream from valve. Thanks
First, be sure gas is available, then I would check amp draw of the gas valve when it is energized. Sometimes the control will only send a ghost voltage with no amperage.
GFM
Hi. Tried replacement valve today (used). Still no gas. Confirmed I have gas upstream from valve. Then I followed your advice and checked both valves for amp draw and it says its drawing amps the whole time, but like .06. Doesnt change after ignitor glows. Sound like bad valve? Thank you.
@@andrewm.4168 Sounds line a bad control board.
GFM
My furnace is letting a rare scent fume when it is on. I just had a shimney sweap because I thought that was the reason for the smell I was getting. Nevertheless, the fumes are still there. It doesn't smell like gas but some type of combustion. Please guide me.
It is probably burnt gas. If its a natural draft furnace(older than 25 years), it is probably not venting properly or there is a crack in the heat exchanger. This needs to be looked into. There is a possibility of CO poisoning. Your best bet is to get a service tech out there. Hope this helps.
GFM
Valve 36G24 205 made a hissing noise and only one burner out of three came on.(one closest to HSI)
Then with no flame sense it goes out.
I allow it only to retry once.
Circuit board blinks normal green.
Stove/oven works fine.
After eight years could my gas valve be dying?
Of course it is Sunday and it is snowing.
The sub. seems to be 36J24 214.
Thank You!
Not the gas valve it's obviously opening that's the hissing your hearing!!
Take out each individual brass orfices and clear them something is stopping the gas from making it to the other burners
Ivan Luis
The hiss is an entirely new sound from listening to it for eight years. A soft tapping on the diaphram side and it works again now. But I an still considering changing it unless I find something else.
First, clean the burners. They have flame spreaders that move the flame from one burner to the others. Could be dirty.
GFM
The only way I can think of is if the manifold pressure is too low. Should be at manufacturer's specs.
GFM
grayfurnaceman
Can you as an expert tell me if these valves can partially fail? Meaning are there ever failures where the valve only opens part of the way? Perhaps the regulator, which is built in, failed? I clean the furnace every fall but it has run for years without failing even once. And the heat exchanger is some kind of titanium alloy, which I imagine accounts for the hefty unconditional warranty. It is a Dayton(York)I do service work too and it drives me crazy not seeing the end result of a weird problem so I will keep you informed.
Hey GRCC Heating Theory Students! Get that special assignment done yet?
Thanks for the great video. My gas valve is not getting any current to it at all. So where do i go from here? Does that mean it needs to be or is there a problem with the power source?
Adrian Loera Remember, the gas valve is only energized for 4 to 7 seconds during a trial for ignition. It should have power after the HSI warms up.
GFM
It cycles again and again but from what I see the gas valve doesn't energize or receive current. Do you think the gas valve needs to be replaced?
Adrian Loera I assume you do not show voltage at the gas valve at any time. If so, its not the gas valve. Its kind of like running out of gas in your car. You don't replace the car, you put gas in it. Now, If the furnace is less than 25 years old, It probably uses a hot surface ignitor to ignite the gas. Is it coming on?
GFM
Yes everything else has current and the surface ignitor is working.
Adrian Loera
did you solve the problem? i have a similar problem now if i unplug the flame senser i will turn the gas on but if i dont put the plug back on quickly then it will shut off
My gas valve is not getting power. I’ve changed the board thinking for sure that would be the issue, as no power is being sent to the valve. The transformer has correct power going to the board. Any thoughts?
The control board will not allow a trial for ignition until the conditions are right. The pressure switch must be proved open, the inducer must prove the venting has no restrictions, the HSI must prove its on, when the gas valve opens, flame must be proved or it shuts down within 4 to 7 seconds.
Any break in the sequence and the sequence stops.
What are the symptoms?
GFM
grayfurnaceman
About a 7 year old Lennox unit. Everything cycles as it should. Fan comes on. Igniter glows. As the relay clicks in the board to send power to gas valve, it all shuts down. I’ve got two units in the attic. Swapped vacuum switch off my working unit to the non working, still nothing. Last thought was the gas valve after board did not work. So I got a 24v source, hooked up to the gas valve (which was disconnected) and it opened. Since I did that though, now the board pops the fuse every time it tries to open the valve...
@@williamsoape7220 If you have not miswired the valve, I have to say the valve is shorted. I know you tested it, but there is nothing else that I can think of.
GFM
grayfurnaceman
For some reason I never checked the ohms on the valve. It’s at around 330. Valve on the other furnace is almost 1k. Wasted money on the board I think
@@williamsoape7220 The valves have a rectifier that sometimes fails.
GFM
GREAT VIDEO.
I have a small leak on top of gas valve around plunger switch. Could i replace plunger switch and save getting a whole new unit?
kenny clark Parts are not available for gas valves. Replace the valve.
GFM
I have a Rheem furnace. I put a used board in because my previous direct spark board would not spark reliably ... intermittently. I had to tap the board to get it to send a spark, then it would engage the gas valve and run fine for a week or so. Now back to where I'm at now....the used board I put in looks very similar. All wires are transferred correctly. The sequence goes; inducer fan, vacuum switch, direct sparks, then blower just blows cold air. I am going to chk the gas valve for amps like you said but I am wondering if it's this board as it's not exactly the same as the original. Is it needing something else to function? It's a 62-24136-01. I tried a ICM 292 board. It did exactly the same sequence. If I put the original back in, the gas valve works fine but maybe just for a week. Any clues as to what's going on?
+DIY FIX GUY Sounds like the board is defective.
GFM
Change thermostat