Troubleshooting Electric Heaters For Air Handlers (Sequencers Explained!)
Вставка
- Опубліковано 31 гру 2024
- Today we start our video series on Electric Heaters. We walk through the basics and some troubleshooting of electric resistive heat for HVAC air handlers and electric furnaces. We look at sequencer functions to help diagnose issues.
I would say this is the best video yet, the other videos i have watched are confusing because they keep switching around with to much unnecessary bullshit. You get to the point. I only needed to see where to connect each wire.
I finally get it because of you what an awesome laid back but perfectly explained
I had a Goodman pancake unit where the heat strips and fan would run non stop even with the unit off, ran new wire and new stat and still had issue, I’ve never messed with sequencer/fan relay so it makes sense this was probably the issue. Thanks for the video!
you gave me some info i needed about sequencers..
im going to school for hvac 5 months in.
thank you for the info.greatly appreciate it
Don't they teach you that in school?
Helpful. I appreciate the encouragement to just take your time and trace the wires. As a new tech I often feel stupid for not being able to immediately figure out how it's wired up by looking at it.
I alwsys block out loose wires like they are their and focus on juts contact points it helps 😅
Laid back but clear presentation. An excellent instructor.
Seriously
Excellent explanation! Thank you for making this video!
Thanks that helped me a lot to understand how the heaters work as a hvac technician.
I work on these kinds of units im glad i found this video
You're amazing, thank you for your very easy to understand explanations. 👍
Nice brother! I didn't know that about the time on and off numbers. Pulling it apart was nice to see.
New to your show wondering how can I get a blueprint of the wiring on the heat element?
I just found your Channel really good video since I work apartment maintenance what's helps me a lot on the fur down units I hope you keep doing more videos especially on fur down units
Glad it was helpful. I’ve been out of commission with cancer for the last 4 months but I’ll be back to making more videos very soon. Thanks for watching.
Wow. First time i find this type of heat strip. I needed that in 2012 when I started hvac. But still worth it to learn.
Broke down perfectly! Thank you
this was helpful in some ways and added questions for me. i have a similar unit that wont fire the element but the blower comes on as soon as i turn on the thermostat. ive replaced the thermostat, the sequencer, the limit switch wired to the element and the element itself. i only wait about 20 seconds of the the blower running and the element not firing before i shut the unit down again. Am i not waiting long enough or is something backwards?
Thank you for the helpful videos. I've run into an issue with my electric furnace that happens atleast once ever couple of days: The thermostat will call for heat, but the furnace never comes on. While testing, the only way i've gotten it to work again is jumping the fan wires (R & G) for a second or two. 5 seconds after I do that, the furnace will kick on again and go off at the specified temperature. Do you know what could be causing this and how to troubleshoot? Last time this happened, jumping R and W did not work.
Thanks for your video. Im going to check out my sisters mobile home furnace. Its blowing cold air.
Awesome video, clear explanation, good pace, love the detail! New subscriber. :)
Thanks for the support. New videos coming shortly
Thanks a ton brother, bailed me out, haven't worked with sequencers in a while, and the secondary property I am working for, that's all they have is heat strips.
Glad it helped man. I’ve been out of commission with cancer for the last 4 months but I’ll be back to making more videos very soon. Thanks for watching.
@@ntexashvac7240 My best friend has cancer also. I'll include you in my prayers 🙏. Thank you for the response.
Golden advice!
Great video.
Hello
Great educational video. thank you very much for your help. I have a question about the low voltage wiring diagram. If we have installed a 24HX5 fan coil with a Goodman Heat Pump Condenser how we may wire the fan coil without a heat strip making it a heat pump system?
Please Help
Thank You
learned alot from this video, thanks!
I love this video, thanks
That was a good video 👍 can you please make a video of reasons why fuse links blow up
Thank you very much for your video. After I replaced these three items: Time-Delay, Fan-Relay, and Contactor (outside). Still, my AC cooling system keeps running and cannot be stopped. Question: Does Sequencer relate to fan-relay and cooling systems?
Great video. I have an issue w my Fahrenheit fuh724 garage heater. It’s has very little use. I noticed when it was working, it would make a clicking sound when I turned on the breaker. Now it doesn’t make any sound and it doesn’t heat up. I’m hoping it’s just a relay. I’m gonna take it down off the wall and try to troubleshoot it now so I figured I’d shoot the issue to a pro first. Any input is greatly appreciated. Thank you, Rich.
If it was one click when you turned it on then it’s mostly likely the relay your hearing or I think the thermostat on those is a fail point too like the Qmark and Marley heaters
Thank you for the quick reply. What I failed to mention is that I have it wired through a Tork timer which when I bypassed it last night, turned out to be the issue. The heater works fine now. Apparently something inside the timer failed. Thank you again. Great help !!
Hi, what gauge wiring is needed for wiring the heat sequencers? Is 10 gauge good enough for the sequencers in the furnace?
Great video. Amazing.
If you have the heat strips running at the same time as the A/C, what would be the symptoms? Would you have super high pressure readings on both the high and low sides, making it appear overcharged? And would your delta T indoors be cool but lower than normal?
Usually In a conventional air handler the heat strips are down stream of the coil so as far as your pressures are concerned they will look to be normal. The delta -T will be low because the cooled air will be heated downstream by the electric heat. The fastest way to diagnose a stuck on heat strip in the cooling months is to amp clamp the line voltage at the air handler while your set to cool. The blower only pulls a few amps so if your getting amp readings like 15amps and higher then you have a strip on. Each strip typically pulls about 20amps but some are a bit lower. But no blower is pulling 15+ amps under normal operation.
@@ntexashvac7240 great info, thanks. I briefly checked a PACKAGE unit last week for a neighbor, only had time for a quick check, high side 507 PSI, low side 170 (r410a). Told them it was overcharged, didn't think to check the heat kit. Heat kit was only installed last year, system is 5 years old. Condenser coil is clean. Delta t is only 9-12 degrees. Been going around my head to check the heat strips, but haven't been back. Could it be anything else besides severely overcharged?
Yea it could be the TXV if it’s a TXV coil or possibly restriction. I would check the evap coil for even temperature across the coil
I've got one like that brand new and just stopped working I changed fuse checked all connections there fine.any hints
What do you call the thing the voltage staying there next to the heat sequencer
Thank so much! Have a Goodman air handler which will not heat past 68 degrees no matter what the thermostat is set to. Tech replaced sequencers and it worked for a little while. Any ideas?
Heat strips could be under sized for the tonnage of the system.
Help a lot thank you
If the heat sequencer is timedelay
Does it take a while for heat to actually kick in?
I have a York electric furnace that blows hot air for about two minutes then I hear a click and it only blows cold after that until I reset the breaker. Any advice as to what you think would cause that would be greatly appreciated!
call a tech
Hi l'm new to your channel and I had a technician out and he used these words. Heat handler has 3 heat bank's and it is a Trane and he said that a limit popped and is not letting the 3rd heat bank is not coming on what is he meaning about that?
My cadet electric wall heater was working just fine. All out of the blue it just started blowing cold air. The fan blows. Tested thermostat and works. Kicks in when i set it at warmer temp but just blows cold. I hit reset button, didn’t work, i reset the circuit breaker, no change. Is there a way to fix it or do i have to go buy a new one?
Good job ,
I gotta check mine. Something is popping and switching intermittently causing the blower to run when it's not supposed to, or not expected to.
Reasons sequencer type of switch is used is to limit the initial current to the heat strip. One stage heat strip dose not need or use sequencer....ad a second stage ....then you need the sequencer because the initial current draw would be way to large
I have the type of sequencer with the wire soldered connections at 4:mins.My fan runs a few minutes and turns off.Élements stay red and fan starts ,but after quite a few minutes.I guess that I cannot test sequencer without power.Thanks great video.
I was In till you lost me at power out of the heat strip on a 220 element said to my self 👀
Had a question on a unit I was working at work ... The breaker is completely off yet it's still getting power and idont know why or how
I changed the sequencer fan relay heat disk and run cap and it worked fine for a few hours then tripped the breaker so I turned everything back on and blew the fan relay so I replaced the relay and same.thing it blew the fan relay again and I turned the breaker box off but when I test it to see if it has power it does and I'm so lost
There is a good chance you have a bad breaker at the panel. If you still have voltage at the air handler when the panel breaker is off then it is usually a bad breaker or sometimes it is wired to multiple breakers and isn’t labeled. Try looking for other double pole breakers in the panel and turn them all off and see if that doesn’t kill power. If you still have power then change out the breaker in the panel this could be your issue.
@@ntexashvac7240 I have the whole entire panel off everything 20s 30s and the double 4p for stove it was all off but idont do breaker boxes got grabbed 1 time and never again
If you have every breaker off in the panel, and you still have power, then try turning off the main service breaker, if you still have power to the air handler after that then there is a serious electrical problem in the house wiring and I would tag in an electrician.
@@ntexashvac7240 copy that thank u sir . There is no main unfortunately so I will call the pros out . I do apartment maintenance and I'm. still learning the ins and outs of HVAC .
I get lost on verifying the sequencer is good. Amy videos on testing them?
I have a heat sequencer that stopped working recently (no heat and no continuity between any of the terminals). It is double switch exactly like in the video and single time timed H30-70 C1-35. Problem is it is so old its not in the record of most distributers and exact replacement or replacement model is not found. Another issue is it is labeled 4-5 , 1-3, and the double brass terminal in the bottom which is completely different from the newer replacements. The closest I found is H30-90 C1-30 but it has M5-M6, M7-M8, and the double brass terminal in the bottom. Can this be used in place of my old sequencer? If so do have to wire it slightly different form the original? The original had element connected to 1 and element 2 connected to 4. It is a 2 element 10KW HVAC electric heating system. I check the elements and both elements have continuity. On mine I also have two what seems to look like two pin elements.
Yes it should work. The timing is approximately the same which is fine. Since it’s only 10k heat there isn’t much fear of it pulling too many amps at startup anyway. Wire it up the same as the old one and you should be fine. Yours may have the high limits built in and that can be why it looks like it’s dual pin on the element. Thanks for watching!!
@@ntexashvac7240 Actually on the element side it looks like there are 6 elements and two thermodiscs one by each set. Four of what looks like elements have only a single terminal while two have two terminals. It looks like I have two different types of elements in two sets. Each set has the 2 single terminal elements (I think this is one element as there is continuity between the single terminals) and the double terminal element. You are saying M5-M6 and 1-3 makes no difference? When I connected it initially fan started up without being turned on in the thermostat. Initially 1-3 was connected to M7-M8 because it was in the same spot on the sequencer as the 1-3 on the original sequencer. Should I connect what was initially connected to 1-3 to M5-M6? From what I understood the number indicates which starts first.
Good stuff. I hardly deal with heat pumps. Down in Brownsville electric heat is king 😂😂
Electric heat killed me when I was starting out so I really focused on that for a long time. Thanks for watching!
How are you running 10kw off of one heat sequencer thats 40 amps on a 25 amp sequencer?
In this particular instance it’s not a 10kw it’s a 7.5-8 kw kit to be specific, but to answer your question, heat sequencers are rated by “single load contact” so each individual contact inside the sequencer has that rating not the entire sequencer has the 25 amp rating. So since most strips are 20amps or less you can safely run 3 strips on a triple stack heat sequencer or 2 strips on a double as most every manufacturer does. You have to think of each stack (contact) as an individual sequencer not the sequencer as a single unit. If 25 was the rating for the whole sequencer then every heat kit out there running 2 strips on one sequencer would be out of spec but that just not the case. Now if we were to double up the strips on one contact we would have to make sure we were below that 25 amp single contact rating or we risk burning it up. Hope that clarifies.
@@ntexashvac7240 okay thank you for taking time to explain it that really helped
Maybe you could solve an issue. Why would the heat strip not come on when everything else is working. Old Goodman system. Everything has continuity, new sequencer and limit switch on heat strip, new thermostat, wired correctly, and all wires test correctly. My maintenance lead and an electrician can't figure why. Also the element has no breaks and does have continuity. The system runs but no heat. New 60 amp fuses as well. The property wound up replacing the entire system but another apt unit is doing the same thing. Any opinions would be great. Thanks
I’m having the same issues with a Goodman did you ever figure out the issue? Currently sitting here cold 🥶
@@lillianm1242 No, we wound up replacing the complete air handler. The only thing I could think of is if one of the wires shorted. Didn't continuity test each wire individually. All components were receiving correct power from to the line in block through to the element. A mystery! Have you shut down the breaker so no power then run your fingers over all wires. Feel for tiny burn marks. We get this all the time. Resident will flip the thermostat switch on and off not knowing there is a delay of up to 5 minutes before the system comes on.
Thanks for the video !
So my ac works fine. But heat doesn't turn on (at least, not the fan. Can't tell about the actual heating). The white wire has no power (at the thermostat). could that be a sequencer issue?
Hey just found your videos, I like all three I watched. Hopefully you come out with more. Thanks
im having trouble with understanding wiring fan relays sequences transformermers are marked ,....limit switches could u plz explain in detail all
Good video!
So there are multiple heat strips and the sequencer powers up one and then allows a delay before powering up the other one? Is that what it's doing?
Correct. There are many different versions of sequencers with different on and off time delays but the concept is the same. The big reason is to keep amp draw down and maximize efficiency.
So I moved in to this mobile home I made a complaint about this furnace inside my 90 days but the dude they paid to fix it left me with this. The lower elements are unhooked.. I cant seem to find the wiring diagram for this furnace. Was hoping for a little help.
Post model and serial number as well as make and I’ll see what I’ve got
Got a furnace with no control/circuit board that blew a transformer (no fuse) replaced transformer and added fuse and blows the fuse instantly when i turn the power on! Any thoughts?
Low voltage short in thermostat wire most likely. Disconnect all thermostat wires from
the furnace then replace the fuse and try again. If it doesn’t blow then you’ll need to track down the short in the low voltage thermostat wires
Im getting power to the unit but not the thermostat what would cause that thanks!
Could be transformer or sometimes there will be a 3-5 amp fuse or even a fusible link. Look for blown fuses if none found then test for 24v at the transformers secondary voltage terminals
Blower motor wouldn’t kick on. I tested resistance in the windings and they read fine. I’m starting to believe it’s the fan delay relay stuck in the open position
The one I took off has a made up jumper wire across one side of the 24 volts. The new one I was sold has a soldered wire across both sides of the 24 volts. Does that matter?
No it doesn’t matter. The proper “M” numbers and proper time delays are what matter. The fixed jumper just eliminates the need for a wire jumper
NTexas HVAC - Old sequencer on one end has,
M1 and M2 and the other has M3 and M4 over M5 and M6. Part #3112-3571 (15SH14) for this one. On Coleman air handler w/15kw strip heat.
New one that Carrier sold me is different.
Part #15SH22. It’s got an extra stack and the “M” numbers are on opposite sides and different spots up and down. There is M1thru M8. I just put M1, etc from old sequencer to wherever M1 was on new sequencer and followed the same way with the other ones.
Is that wrong?
No that’s the best way to do it given the new part you have. The numbers designate which strips come on first and likewise which ones go off first. You can get it a little wrong and be ok it’s just meant to not allow all strips to come on at the same time and risk tripping a breaker. The new one just has and extra switch for more strips. What you did is right.
NTexas HVAC - Really appreciate ur time. Now need to figure out why elements will not come on. Elements ohm out good, heat limits as well all good, sequencer wired, transformer tested all good, new Honeywell stat installed and all setup functions set. Only thing left in this old beast is the blower relay. Just to test with stat face off, I can jump R and G at stat base and fan comes right on but when I jump R and W I get nothing. I have 24 volts between R and W at stat base too. Fun times ahead.
Have you checked for 24vac at the sequencer? Make sure you are getting 24 when call for heat. If not start back tracking control voltage
I have a trans electric unit, coils heat up and when it’s time for fan to come on, the coils turn off. Any ideas?
Does the fan come on after the coils go off? Also there are high temperature limit switches on the heat kit, if the fan isn’t coming on it can trigger those and force a shut down. Which model number air handler do you have?
I currently have an electric furnace and, with the thermostat off, the sequencer is turning the heat elements on. Thermostat off. Unit keeps heating. Fan off.
Just random turning on and off of heat elements, this issue started after I put everything back together after a deep clean.
So the sequencers are working, but im not asking for heat.
Any ideas?
So what’s happened most likely is the ceramic rod that holds up the contact inside the sequencer has broken. When that happens the sequencer actually fails in the on position so it’s actually not working properly because it’s heating without a call for heat. The intermittent on off comes from the high limit switch interrupting the electric flow and heating as the temp inside the heat kit rises due to no airflow because the fan is off. You’ll need a new sequencer.
@@ntexashvac7240 thanks for the quick reply. I watched a video, may of been yours, of a sequencer taken apart and explained how it works, along with your reply im confident that is the issue. My unit is 30 years old, and has 2 separate sequencers, im going to replace both. Thank you for your help!
@@ntexashvac7240 do you think its safe to leave the unit on, until parts arrive, and have it still cycling on the heating elements ?
@@benm1751 I would not leave it powered up if it’s going on and off, if the limit switch fails you could have a an over heat issue that could damage the heat kit or worse.
@@ntexashvac7240 mt fear exactly, I will leave it off thank you
Good video.
How do you test the sequencer for continuity?
Do you still need help with this? Let me know.
Great
I have problem ido not why tranformer burnet evrytime when turn on
Is it normal for the fan to kick on first and then ~20 seconds later the heat strips come on? One would think that heat should come on with fan.
It is common especially in older units since the fan relay is wired directly to the heat call. You can swap the the current sequencer with one that has a delay and that will
Solve that, or you can wire a time delay between the fan wire and fan relay, that will cause a time delay on the fan to keep it from coming on first. Depending on what make and model and age it is would depend on the best course of action but it is an easy fix
Would the heat sequencers effect my blower ? Weird situation so the emergency heat strips would work , fan would work , but as soon as I put it in on heat pump blower would run then stop and make a super loud noise
Awesome
So why would it blow cold when heat is on
At 4:59,what did you say? I can't hear it clearly. LOL The problem the customer would have? no hot strips on even when my air is on??
The problem the customer would have is the heat strips would be on with the AC on. It would cause the AC to seem to be running normally but since the strip is on your delta T would be very low.
And your power bill at the end of the month will be about 5 times as high as it would normally be.
Thanks
I have a ? Heater comes on blows cold the after a few gets hot
Central heat not heating, turn on it blow cool air want heat, element sensor honey well AC and Heat unit
How do I check a heat sequencer with multimeter ?
+Arturo A the easiest way is check for 24v on the bottom terminals. And to check if the sequencer is open or closed you would check ohms on the heat strip terminals of the sequencer with the heat strip wires disconnected. OL means it’s open, if you get an ohm reading then it’s closed. If you need better help let me know I’ll post you a video
Do another video checking please sir
👍🏻
How would I know if my heat strips are on if my air is off?
The easiest way is by using an amp clamp meter. If you clamp the main wires going into the air handler and you get an amp reading of say 10 and above, then you have strips on. Nothing else in the air handler pulls that high of an amp load except heat strips. Typically each strip pulls 15-20 amps. Hope that helps, if you need me to make a video showing how to do that test let me know and I’ll get one up
@@ntexashvac7240 I need that video right now lol. One of two heat strip is stuck on. I believe there is a temp safety switch that cuts power (sorry can’t remember the parts name. So electric air handler, no heat pump, runs normally. Except when the thermostats has kicked everything off I can hear (a relay?) engage and one of two coils turns on. Runs for a few seconds and kicks off. Does this continuously. I smack the fan relay and it quits. I’m thinking the fan relay is stuck on.
@@dennisrandall8040 if it’s a Goodman, Amana or a Daikin it’s most likely the fan relay, it’ll look like a sequencer but it’s the relay and it’ll feed the strips. Also could be a bad sequencer that’s causing the strips to be on
What are the symptoms if a sequencer is stuck on?
The heat strips will constantly be on. If you have and amp clamp meter you can clamp the high voltage wires and look for amp draw. Anything about 1-5 amps will
Indícate a strip is on. Typically 15-20 amps per strip
I have a Goodman electric furnace that stays energized even when power is off
Find where the power starts and follow it til it stops, then out what’s stopping it
Where does the white wire go to
The white wire on the bottom of the sequencer in this particular unit would hook up to a control board and supply 24volts when you call for heat at the thermostat.
It can also be wired directly to the heat wire from the thermostat in some models. On the thermostat it may be either “W”, AUX, or Emergency. It is what actuates the sequencer and starts the heater
So basically if you’re a DIY kinda person cut the power. Take pictures, Swap like for like?
I need a more detailed wiring .
I just learned. Fuck yea
Went on a call today the homeowner had a new ecobee tstat installed he said now it says the auxiliary heat stays on so I thought they put the white wire in the wrong place but no it was saying auxiliary heat on but really the tstat wouldn't bring the strips on even set to emergency heat I put a Honeywell t8000 tstat on everything worked as it is supposed to