Excellent video! Some solid suggestions/comments from readers! But other comments shows they truly don't understand to the level that's required to perform this modifications!
I was working on a similar project- a contactor in an electric furnace burnt on the line side. I almost did the same thing as the video. Two 10 wires from the breaker to one side of a new contactor. I was worried the wires were two small to handle 40 amps so I used the original 6 wire used by the last company. Currently waiting to pick up a lug Contactor so I can fit those big wires safely.
This is a good video. I also like to the solder the crimp on connectors. That way you will never have a problem at the crimp end as long as they are tight under the screw.
For those that are working on an electric furnace, I have found a GOOD heavy-duty 1/4" quick connect - NOT the crappy shyte sold for general use. It is part number P-HT-BFF-250 by WiringPro. It is billed as a "high temperature' part and is WAY more substantial than anything else I have seen - there are no thin spots and it grips the blade with considerable force - great for high-current work. I recently had the top half of one sequencer burn away - GONE! - and damaged some wiring in the resulting fire. I believe the problem started from an arc on a standard quick-connect. I have replaced all the high current wiring in my furnace with the WiringPro connectors. Although sold as 14Ga connectors, they can be opened slightly (with a nail or a watchmaker's screwdriver) and then both crimped and soldered to 12Ga wire. (I didn't try them on 10Ga.) If you are having trouble with quick-connects getting hot, try these connectors! (Unfortunately their web page appears to be down at the moment.)
There are 2 problems these connectors must deal with. One, adequate friction to keep voltage drop down. I have used these connectors and they work well in this way, although not spectacular. Two, high temperature connections. For the most part, this is meaningless. High temperature connectors are made for use in high temp environments. Not high temps caused by poor connection. These high temps are much too high for any connector to survive. Also, the sequencer with the burned top is common for this type of sequencer and is sometimes but not always caused by the contacts inside making poor contact and burning up. Sometimes, the top with the connections is completely separated from the sequencer with the connection actions still firmly attached. Not too thrilled by the 14 to 16 ga wire size that must be adapted and therefore possibly causing a poor connection. The only real solution to this problem is to replace the sequencers with contactors and use ring terminals for the connections. This is a viable alternative that is used by some manufacturers as original equipment. GFM
Have you ever used a sequencer to control more than one contactor? That would take the high current off of the sequencer and yet allow the sequencer to control the time delays.
Thank you GFM for your incredible repository of 1000 plus videos on HVAC ! I've watched about 500 or so and loving it. Just one observation about crimping terminals. As a previous viewer commented you are using the crimper incorrectly. Insulated terminals should be crimped with the smooth mouth portion of your crimper according to industry standards. If you want to use the non-insulated part of the die then pull the insulation down, crimp on the opposite side of the split, then slide it back up. But better to use the smooth portion of the crimper that is usually labeled as such. Perfect crimping leans toward making a gas-tight crimp where the barrel of the terminal envelops the wire strands squeezing out the air space which leads to less corrosion and ultimately less resistance. I personally don't think the pin type crimper is a good idea even for non-insulated crimps because the force of the pin is so concentrated that it can crush wires and the actual contact of the rest of the barrel to the strands is minimal. The best crimpers are ratchet style and non-insulated. They have a two sided die where the split of the terminal barrel is gently rolled into the center and the rest of the barrel is tightly squeezed around the strands excluding air. However almost no one in hvac service uses that type of crimper except for the manufacturers. The better type of insulated crimpers are ratchet style and the smooth faces are wider than cheaper crimpers. The best insulated terminals are the heat shrink type that helps to seal out moisture. Avoid using the cheap harbor freight type insulated terminals for high current because the pvc insulation can be very brittle and the actual gauge of the metal terminals is very thin and the plating is not the best. They are ok for low voltage/low current but are definitely not for high current like the contactor. Also great recommendation about using ring terminals if possible rather than female spade connectors. The cheap female spade connectors lose their springiness with repeated heat/cold cycles thereby potentially creating higher resistance and eventual failure. Thanks again for your incredible contribution!
If you use ring terminals that means drilling the terminals on the sequencer and than a bolt to connect.My Question if the sequencer controls the contactor for opening and closing the contacts in such a short and frequent time , will it be hard on the contacts.
I appreciate you taking the time to make this video, and your level of knowledge on these things. It seems to me, though, that this is more of a video displaying the fact that you did something than an explanation of of 'how to' do that thing. A step by step tutorial on which wire goes to which terminal and why would make it more of a 'how to'. I hope that doesn't come across as overly critical. No offense intended.
It's fairly simple to follow. If you were to replace all necessary wires in your old sequencer and breakers, the remove your sequencer and just transfer those wires over to the contactor it should be pretty self explanatory if you know how your sequencer works and what is on what circuit.
There are no aluminum connectors. It is not suitable for this applications. The connectors are copper. Stainless is for connections that are exposed to corrosion. No connector will hold up to heat from a poor connection. The connections must be clean and tight. Stainless does not conduct as well as copper, so it should not be used for high amps. I have seen so many of these stainless connectors burned up because the connection was not done well. GFM
Wow.. Thank you. He took the fuse box out the walls to make sure it wasn't anything dealing with the fuses.. ) but ok..Thank You so much.. More diagnoses is needed )
That's a very interesting approach I like it. Lots of variables can be explored in your approach, I was thinking you could even add another contactor with a inline time delay device to get a delayed start to the third coil or even 2 stage it. Very informative and you get straight to the point. thanks
I can think of one more safety device : an air flow switch. If for any reason the blower fails to kick on the the elements will not come on thus saving the elements from excessive overheating.
So this trick works even better with the systems made today because almost ALL of them have a fan relay board that already will clear the heat from the handler.
I live in a mobile home with furnace heat.When the furnace heat kicks off and the blower sequences down,it blows cold air into the home.This sucks.I think im going to replace my sequencer with a contacter.This should fix the problem with the "cool"down of the sequencer.I like the idea of the contacter kickin off when the temperature is met.Seems like it would save money.
Yep, the electrical systems in these units are just as complicated as the electrical systems in a vehicle except with these you're dealing with high voltages
Hi GFM! Great video. Is there any way you could do up a ladder diagram of what you did in the video. I would love to keep a copy in my truck with me. Its a little hard on my laptop screen to see how all the wires are going. Thanks a lot.
Great video. Im tired of crawling under the house and replacing these sequencers. I'm going to do this conversion. I have a question though. My furnace blower also must run with my AC so I would not be able to use one leg of the heat contactor to pick up the fan motor. I assume I would need a third contactor for the fan alone. If you could maybe explain the correct wiring for a 4 element furnace with AC that would be helpful. Thanks.
@@grayfurnaceman yeah after studying the wiring diagram I understand how it was designed. Honeywell programmable thermostat took me a while to decipher with my meter. Want to run my heat pump / electric backup system like a basic heat and cool system. Reversing valve is bad I think and will just leave it in ac position for now. I think I can do this changing one wire and the correct programming of the thermostat.
Great instructional video. The total furnace draw amperage according to the amp meter reads 68.3 amps but the circuit breaker is rated at 60 amps, is it the result of energizing the heat strips all at once without a timed sequencer? Thanks for sharing again.
When you demonstrated crimping a #10 ring connector you said you crimp on the back side of the connector ( that's the way I always did it ) yet when you showed a close up of the installed contactor your crimps were on the top side of the ring connector?
+Tim Spriggs Some furnaces come with them. There is no real value to using an SSR. I can pretty much guarantee it will not last as long as a mechanical one. Also, I haven't seen one that was rated at 50 amps. GFM
First thank you for your informative videos. I have an older Intertherm furnace (with 3 x 20amp elements and fuses), 2 sets of 30amp, and 60amp. Have 50amp double pole breaker at my box . One would think that one 30 and 60 amp fuse would correspond to each pole of the breaker. I cleaned up the wiring with new 10guage. It has a 40amp contactor for the elements and fan. It threw the breaker yesterday after running for a week. The main questions...do I need a 50amp contactor, what one did you use above, the Honeywell is $100 and maybe overpriced....Or does this sound like a wiring issue, I duplicated the previous wiring but that doesn't mean it was wired correctly in the first place. Thank you, and yes I will contact a tech if you think it is a wiring issue.
Your contactor is probably a bit small. 50 would be better. The Honeywell contactor is used because it is quiet operating. Any contactor with the rating will work. Do you have just a single 50 amp breaker in the panel for your furnace or are there 2? GFM
Thanks for the video GFM. Two quick questions: 1. Why did you choose a two pole contactor over a three pole? 2. Whats the reasoning behind two number 10 gauge wires from the contactor rather then one heavier gauge wire? I assume all you had was number 10 wire and thus just doubled it. Just looking to learn.
PHC Apprentice If your furnace had more elements, you could use a 3 pole. This one had 4 elements. The #10 wire is used for each element, as each element is 5000 watts or 20+ amps. Hope this helps.GFM
Hmmm... my furnace states the breakers on it, is for short circuit only and not for overload. But then both breakers are 60 amp. Interesting, I'm learning from your videos on furnaces, after watching this video I now know my furnace does not have sequencers. Lol since I bought this furnace I thought it did... it all makes sense now why all my elements were kicking in at once. I kept thinking what the???... little did I know. Thanks, you just answered a question I had asked myself 100 times. PS, furnace guy, you really thing contactors are better than sequencers?... just askin, it seems like it would cause a furnace to use more electricity over time???
If you test across the contacts during a call for heat, after enough time has passed for the sequencer to close, you should read 0 volts. 240 volts means the contacts have no closed. GFM
I'm currently working on this same style furnace the issue is the blower won't shut off after the thermostat is satisfied could this be the contactor is bad ?
If you are going to use a contactor, use a 3 pole contactor ( one per element). It is not a good idea to double lug and you will reduce the load on the contacts.
You could certainly do that, but if your contactor is rated for the amp draw used, there is no overload. Contactors are commonly double lugged in the industry. GFM
thanks Gary, need some advice i have a question maybe you can help. i'm up north, first freezing cold spell since the winter, first time aux heat strips in use in the air handler since winter (Trane 4tee3f37b1000aa). When the aux heat starts, there's a machine gun rapid fire/chatter sound at the air handler, right about where the 20KW line comes in. pretty loud i'm not really familiar with relays or contactors but could it be relays that turn the strips on and off that can make the noise?? Once the heat gets going and the fan is up to speed, noise stops, and then starts again a bit when the heat cycle shuts off. I'm still getting aux heat and the fan is running smoothly and is set to ON, outdoor HP heating fine otherwise. I'm DIY have changed blower motor module and capacitors but no relays. system is 12 years old. 1 have 4 heat strips x 5kw each
The chattering indicates the control circuit has excessive impedance. The coils of the contactors are not getting enough power. The first thing I would be looking at is the thermostat. GFM
@@grayfurnaceman thanks for the quick reply Gary. From the tstat display everything looks normal. Can you suggest specific troubleshooting steps- what I should be doing/looking for inside the air handler? do you mean that the control signal from the tstat is only opening the circuit partially at the heat strips and what might be failing exactly to cause this (relay/contactor/sequencer?), does that indicate mechanical failure/physically damaged/burnt parts (what and where), and/or loose wires or connections? or more like a board? I'm not that familiar with electrical but i can methodically identify specs and replace parts and reconnect wires based on existing config. my budget is very limited so i need to figure this out myself like in the past. sorry for the long question.
Do you have a part number for a 3 pole contactor? Does the contactors turn on and off from the 24 vac directly from the thermostat? I didn't see you show that part.
dpeagles I guess the point is, what is more important, whether it works well or whether is passes UL. I guess its up to the individual technician. Thanks for the thoughts.GFM
Since there are also 60 & 30 amp breakers at the main panel, if the 30amp here in the air handler is bad, why can I not just bypass the breaker in order to get them up & running quickly? It still has the 30amp at the main for circuit protection. Nearly all brands do not even have breakers at the air handler. Nordyne does it this way though and not sure why.
Here is the problem with bypassing the breaker. Because the manufacturer installed it. Its that simple. You are correct, the circuit protection is still there. However, if there was a fire, you would be blamed. Even if your actions had nothing to do with the fire. GFM
ok i did it but i had to put all 3 elements on the 60 and the fan and transformer on the 30 or the breaker kicks out on the 30 it is working now is that ok i changed all 3spring elements and limit switch
+scotty dog If it immediately kicks off, look to your wiring. If it kicks off after some time, be sure the terminals at the breaker are tight and check amp draw of the circuit. I have done this dozens of times. It works well. Also, if you put 3 breakers on one 60 amp breaker, the breaker will kick off after some time. GFM
A relay (contactor) is simpler. I guess the only downside is the possibility of noticing the lights blink when all three loads come on at the same time.
That has been the argument against the use of contactors for over 50 years. I would say that may have been true when the grid did not have the capacity it does now. I have not seen that issue happen for many years. GFM
. I have a Good man electric heater and a serviceman said it need a control panel but when I call another company i the deal with electric heaters they mention that it need a Heat strip.. *The heater won't come on so I'm wondering just from hearing about the heater won't come on,( The blower comes on) but there's no heat what would you suggest,?
Usually these units have several heat strips. If one has failed, you should still have some some heat. It sounds to me that neither one has done a complete diagnosis. GFM
I live in a rural area now and although my panel specifies using 105C wire only it is unavailable unless I want to drive about 60 miles. Is there any practical reason not to use thhn/thwn2 ?
I am having a problem where the fans will not cut on by the thermostat but will cut on my the fan switch. I had the same issue with the burnt limit switch could the problem be the sequencer?
U could also use 2 contactors and a delay on make timer. P.S. your not using your crimpers correctly. your getting a hole because that's for non insulated connectors. go all the way to the bottom. that's for insulated connectors. good video though
How much of a local brown out will this cause? Over time, modern electronics are extremely vulnerable to brown outs that aren't even noticable visually.
One question I have is if your using a 50 contractor and your pulling 65 amps total. Why is this contractor not to small. Is it because each side of the contractor can handle 50 since it's a double poll.
I am thinking about replacing my sequencers with a CONTACTOR. I would like to know if my furnace also has Air Conditioning if this is a cause for concern?
@@grayfurnaceman Thanks for the quick reply. I ALWAYS have my fan on at all times. So I will wire it on (thermostat FAN on switch). That should work fine, your thoughts?
Received my Honeywell contactor today. Where can I get 10awg wire??? I went to 4 different hardware stores and they don't sell "stranded" 10 gauge. Could you point me in the right direction please. I will get it online but would like to know brand type etc. Thank you very much if you could help me with this.
I think the breaker is rated for 50 amps period not each leg or terminal. Cannot put 50 amps on one leg than 20amps on the other. On a regular breaker if using for heaters you half to depreciate the breaker by 80% example 80% of 50= 40amps
I have a quick question i hope you can help me confirm an issue with my furnace. The fan kicks on when the thermostat is off. I know the thermostat is good. The fan kicks on for 10-15 minutes several times a day. Control board issue? Is this normal? Any help would go along way. Many thanks!
+arcdraw your limit is breaking on your gas furnace not enough airflow through the heat exchanger or heat strips are overheating due to covered in grime
So the question I have is the sequencer has a purpose to run the fan after the strips shut off. The question is how efficient is this do the limits pop a lot or do you tell the customer to leave fan to on in the thermostat switch? How many call backs do you have once a year once in 2 years just curious not trying to bust your balls.
+andy sharp The sequence of the electric furnace is to start one element and the fan first. The other elements sequence on some seconds later. When the thermostat is satisfied, the elements shut down in the opposite sequence with the last element shutting down as the furnace fan shuts off. The fan normally does not run after the last element shuts down. Leaving the fan on is not necessary. Efficiency of the electric furnace is essentially 100% as there is no stack loss. Callback ratio for me was around 3%. Hope this helps. GFM
Basically I'm trying to round up the parts to save money then I'll call in a professional to wire it ... it has been difficult acquiring these contactors I don't care about the noise what was the model used in this video? I have a 5 element furnace so I like the idea of adding a second contactor and installing a inline time delay device any help would save my family money would be great
The contactors should be available from any electric supply house. 50 amp resistive contacts, 24 volt coil. The contactor used for the single element is a 30 amp resistive 24 volt coil. I don't see the need for the time delay. GFM
I just did this to my heating system I plan on doing a heating test it will take 9 heat ups and see how much time time and wattage to heat it up in the following configs 5KW at fan speeds low med and high 10KW low med and hi and 15KW low med and hi and I'll calc the data and make a graph give me a few weeks....
It does not. Several furnace manufacturers use contactors in their furnaces. The reason for sequencers to reduce initial amp draw came from the 1960s. At that time there were many pole transformers that were not designed for those high loads. That time has passed. GFM
the amperage went up to 68 amps , and the contactor is rated to 50 only eventually the contactor is going to get burnt sooner , they are taking too much heat
The contactor is rated at 50 amps per pole. The original clamp was around all 3 element wires. You could run up to 100 amps thru both poles of the circuit. GFM
I have 5 elements I will ask the service tech to install 2- 50 amp contactors 1- 50 amp contactor for two elements1- 50 amp for three elements 1- 25 amp contactor for the blower?
+Jeff Booher One 50 amp contactor will operate 4 elements breaking one side of line. The first element and the fan can be operated by one 25 amp contactor. If you want to separate the fan from the first element, you can use one pole for each. Hope this helps. GFM
I have done it and the lights do not dim. The sequencers were designed to be used when pole transformers were not designed for the high loads we have now. They pretty much stopped using the smaller transformers in the 1970s. GFM
None the less you are altering or eliminating the factories control features and in my country you are not allowed to do so ,without the governing authorities permission so stop showing people how to do stupid things...just fix it properly and it will last another 20 years.
Hi. I’ve heard this statement about transformer load and sequencers before. Perhaps you could explain to me how a sequencer lessens the load on your transformer. I can’t wrap my head around it. It makes no logical sense to me. If my furnace draws a 100 amps. It going to draw that same amount with or without it sequencers. Thank You
I was wondering I had havc guy HV AC guy come in here and my control board is burn up and he replaced it with a contactor but he didn't hook up the emergency heat my question is how does that work where those low voltage wires hook up to
with me, i think the way you replace sequence by compressor contactor not a good idea. if you do so when call for heat, too much power go to all 3 heating elements at the same time, making breaker shut off easily
Electric elements have no inrush of power, so they will not kick off a breaker. Note also that Trane heat strips all use contactors to control the heat strips. The idea that turning on all strips at once will brown out the circuit is a myth. GFM
Proper electrical design requires the breaker load be approximately 80% or less. Given typical 5kw elements draw 20 amps each, then the breakers have amp headroom. Remember sequencers end up running all elements at once for long periods during cold weather. The key is proper breaker and wire sizing which is a constant either way. Finally the inrush to worry about is the AC compressor, often exceeding 130 amps on startup even though the breaker size is 30 or 40 amps. Breakers have thermal delays to accommodate large initial inductive (motor) loads.
dont remove the sequencers,, they bring the heat up in stages and then down in stages , which provides a nice gentle heat,,,and also the fan is to run after the heat is off to blow the residual heat out of the plenum.. ,, this is a dangerous video.
Sequencers do bring up the heat in stages, originally to ease load on pole transformers when these transformers were sized smaller. That need is no longer there. Most sequencers have a life span of 1/5th that of contactors. I cut my teeth on these things and after replacing them sometimes every 2 years, found that Honeywell made quiet operating contactors for just this application. Heating elements have virtually no thermal mass and all the heat is removed by the slowing fan. There is no such thing as gentle heat. All elements coming on at the same time preheats the duct work to reduce cold air on startup. Some manufacturers (such as Trane)use contactors for all their electric heat strips. So much for the dangerous video. GFM
Using a contactor to immediately energize the elements will have no effect on energy efficiency. When the elements are turned on, they are on and using energy. There is virtually no thermal mass in the elements. When they go off they are off. The energy is off. The heat is gone. Sequencing elements on and off was originally used because the pole transformers were not capable of accepting large loads all at once. Modern transformers are easily capable of handling this load. GFM
If it pure electrical heater may not much difference . If use with heat pump as auxiliary heat , auxiliary heat may not need to turn on all before return to regular heat (coil).the less auxiliary heat been used ,the less energy consumption.
Excellent video! Some solid suggestions/comments from readers! But other comments shows they truly don't understand to the level that's required to perform this modifications!
I was working on a similar project- a contactor in an electric furnace burnt on the line side. I almost did the same thing as the video. Two 10 wires from the breaker to one side of a new contactor. I was worried the wires were two small to handle 40 amps so I used the original 6 wire used by the last company. Currently waiting to pick up a lug Contactor so I can fit those big wires safely.
This is a good video. I also like to the solder the crimp on connectors. That way you will never have a problem at the crimp end as long as they are tight under the screw.
+neutrodyne Good thoughts.
GFM
Best to use a high temp silver solder not the cheap solder used in a transistor radio circuit board.
Thanks for all the tips, I had to do this one cold night because we carry contractors but not sequencers and a little lady needed heat.
Yes , and it really works.
GFM
Thanks for being very clear on what you’re teaching. I am learning stuff all the time!
Welcome
GFM
Tried this the other day and it worked like a champ. Thanks for the insight.
Welcome
GFM
As a person who just was curious about something random, that thumbnail is intimidating
For those that are working on an electric furnace, I have found a GOOD heavy-duty 1/4" quick connect - NOT the crappy shyte sold for general use. It is part number P-HT-BFF-250 by WiringPro. It is billed as a "high temperature' part and is WAY more substantial than anything else I have seen - there are no thin spots and it grips the blade with considerable force - great for high-current work.
I recently had the top half of one sequencer burn away - GONE! - and damaged some wiring in the resulting fire. I believe the problem started from an arc on a standard quick-connect. I have replaced all the high current wiring in my furnace with the WiringPro connectors. Although sold as 14Ga connectors, they can be opened slightly (with a nail or a watchmaker's screwdriver) and then both crimped and soldered to 12Ga wire. (I didn't try them on 10Ga.) If you are having trouble with quick-connects getting hot, try these connectors! (Unfortunately their web page appears to be down at the moment.)
There are 2 problems these connectors must deal with. One, adequate friction to keep voltage drop down. I have used these connectors and they work well in this way, although not spectacular. Two, high temperature connections. For the most part, this is meaningless. High temperature connectors are made for use in high temp environments. Not high temps caused by poor connection. These high temps are much too high for any connector to survive.
Also, the sequencer with the burned top is common for this type of sequencer and is sometimes but not always caused by the contacts inside making poor contact and burning up. Sometimes, the top with the connections is completely separated from the sequencer with the connection actions still firmly attached. Not too thrilled by the 14 to 16 ga wire size that must be adapted and therefore possibly causing a poor connection.
The only real solution to this problem is to replace the sequencers with contactors and use ring terminals for the connections. This is a viable alternative that is used by some manufacturers as original equipment.
GFM
Have you ever used a sequencer to control more than one contactor? That would take the high current off of the sequencer and yet allow the sequencer to control the time delays.
I have not. Except in very rare circumstances, energizing all elements at the same time causes no problems with brownouts.
GFM
I think you just solved my problem BRAVO
These lessons are very well done, very helpful, and enjoyable too. Thank you GFM.
+Jim Rr Welcome
GFM
Thank you GFM for your incredible repository of 1000 plus videos on HVAC ! I've watched about 500 or so and loving it. Just one observation about crimping terminals. As a previous viewer commented you are using the crimper incorrectly. Insulated terminals should be crimped with the smooth mouth portion of your crimper according to industry standards. If you want to use the non-insulated part of the die then pull the insulation down, crimp on the opposite side of the split, then slide it back up. But better to use the smooth portion of the crimper that is usually labeled as such. Perfect crimping leans toward making a gas-tight crimp where the barrel of the terminal envelops the wire strands squeezing out the air space which leads to less corrosion and ultimately less resistance. I personally don't think the pin type crimper is a good idea even for non-insulated crimps because the force of the pin is so concentrated that it can crush wires and the actual contact of the rest of the barrel to the strands is minimal. The best crimpers are ratchet style and non-insulated. They have a two sided die where the split of the terminal barrel is gently rolled into the center and the rest of the barrel is tightly squeezed around the strands excluding air. However almost no one in hvac service uses that type of crimper except for the manufacturers. The better type of insulated crimpers are ratchet style and the smooth faces are wider than cheaper crimpers. The best insulated terminals are the heat shrink type that helps to seal out moisture. Avoid using the cheap harbor freight type insulated terminals for high current because the pvc insulation can be very brittle and the actual gauge of the metal terminals is very thin and the plating is not the best. They are ok for low voltage/low current but are definitely not for high current like the contactor. Also great recommendation about using ring terminals if possible rather than female spade connectors. The cheap female spade connectors lose their springiness with repeated heat/cold cycles thereby potentially creating higher resistance and eventual failure. Thanks again for your incredible contribution!
Thanks for the thoughts.
GFM
If you use ring terminals that means drilling the terminals on the sequencer and than a bolt to connect.My Question if the sequencer controls the contactor for opening and closing the contacts in such a short and frequent time , will it be hard on the contacts.
Thanks for taking the time to make another great video. My instructor told me about your channel and as a newcomer to field I really appreciate it.
jmam12345 Welcome.GFM
I appreciate you taking the time to make this video, and your level of knowledge on these things. It seems to me, though, that this is more of a video displaying the fact that you did something than an explanation of of 'how to' do that thing. A step by step tutorial on which wire goes to which terminal and why would make it more of a 'how to'. I hope that doesn't come across as overly critical. No offense intended.
It's fairly simple to follow. If you were to replace all necessary wires in your old sequencer and breakers, the remove your sequencer and just transfer those wires over to the contactor it should be pretty self explanatory if you know how your sequencer works and what is on what circuit.
Crimp the back side. Good info man. Will deffinatly start doin that
Merry Christmas
GFM
There are no aluminum connectors. It is not suitable for this applications. The connectors are copper. Stainless is for connections that are exposed to corrosion. No connector will hold up to heat from a poor connection. The connections must be clean and tight. Stainless does not conduct as well as copper, so it should not be used for high amps.
I have seen so many of these stainless connectors burned up because the connection was not done well.
GFM
The factory uses a a coating to make them make better contact.
GFM
This is my favorite video of yours
Excellent video. Very well described and video quality is excellent. I will use this to troubleshoot my emergency heat elements.
+bruce consigner Merry Christmas.
GFM
Wow.. Thank you. He took the fuse box out the walls to make sure it wasn't anything dealing with the fuses.. ) but ok..Thank You so much.. More diagnoses is needed )
That's a very interesting approach I like it. Lots of variables can be explored in your approach, I was thinking you could even add another contactor with a inline time delay device to get a delayed start to the third coil or even 2 stage it. Very informative and you get straight to the point. thanks
+rey abbey Many electric furnaces were originally set up with 2 stage. Merry Christmas.
GFM
I can think of one more safety device : an air flow switch. If for any reason the blower fails to kick on the the elements will not come on thus saving the elements from excessive overheating.
That was very instructive thank you very much for your teaching God bless
Welcome
GFM
So this trick works even better with the systems made today because almost ALL of them have a fan relay board that already will clear the heat from the handler.
Another great video gray.
Great Video Grey! thanks for posting
Emin HVAC WelcomeGFM
I am a big proponent of electric resistance heat!
I live in a mobile home with furnace heat.When the furnace heat kicks off and the blower sequences down,it blows cold air into the home.This sucks.I think im going to replace my sequencer with a contacter.This should fix the problem with the "cool"down of the sequencer.I like the idea of the contacter kickin off when the temperature is met.Seems like it would save money.
Thank you so much !! This really helps
great job love your work
Very well said!
Thanks !
This videos help a lot
jose p Murillo WelcomeGFM
Great job!!!
Yep, the electrical systems in these units are just as complicated as the electrical systems in a vehicle except with these you're dealing with high voltages
Good vids, Keep em coming!
Twrecks92 There are more.GFM
Hi GFM! Great video. Is there any way you could do up a ladder diagram of what you did in the video. I would love to keep a copy in my truck with me. Its a little hard on my laptop screen to see how all the wires are going. Thanks a lot.
agreed thanks for the video
NICK-O find a diagram?
The opening disclaimer 🤣🤣🤣🤣
I wish you could have incorporated info on the 24v side and the other relay to the left
If I had access to 3 phase, I would split the 3 elements 1 per phase so as to spread the load more evenly.
nice info with video!
Thanks for the support.
GFM
thanks for video...
Well done .....
Thanks
GFM
Great video. Im tired of crawling under the house and replacing these sequencers. I'm going to do this conversion. I have a question though. My furnace blower also must run with my AC so I would not be able to use one leg of the heat contactor to pick up the fan motor. I assume I would need a third contactor for the fan alone. If you could maybe explain the correct wiring for a 4 element furnace with AC that would be helpful. Thanks.
You could simply use the existing fan relay normally closed contacts connected to the contactor.
GFM
@@grayfurnaceman yeah after studying the wiring diagram I understand how it was designed.
Honeywell programmable thermostat took me a while to decipher with my meter.
Want to run my heat pump / electric backup system like a basic heat and cool system. Reversing valve is bad I think and will just leave it in ac position for now. I think I can do this changing one wire and the correct programming of the thermostat.
Great instructional video. The total furnace draw amperage according to the amp meter reads 68.3 amps but the circuit breaker is rated at 60 amps, is it the result of energizing the heat strips all at once without a timed sequencer? Thanks for sharing again.
Francisco Castellanos Actually, both 2 elements are on the 60 amp and 1 and the fan is on the 30 amp. Thanks for the thoughts.GFM
When you demonstrated crimping a #10 ring connector you said you crimp on the back side of the connector ( that's the way I always did it ) yet when you showed a close up of the installed contactor your crimps were on the top side of the ring connector?
You are looking at the bottom of the connector. They are installed upside down.
GFM
that's cool that you figured out how to upgrade it. Perhaps they shd have made it that way. But.... why not use solid state relays (SSRs)?
+Tim Spriggs Some furnaces come with them. There is no real value to using an SSR. I can pretty much guarantee it will not last as long as a mechanical one. Also, I haven't seen one that was rated at 50 amps.
GFM
grayfurnaceman also, finding one that is SPDT is like finding hen's teeth.
+Tim Spriggs SSR tend to fail closed.
+Tim Spriggs SSR tend to fail closed.
+Tim Spriggs SSR tend to fail closed
First thank you for your informative videos. I have an older Intertherm furnace (with 3 x 20amp elements and fuses), 2 sets of 30amp, and 60amp. Have 50amp double pole breaker at my box . One would think that one 30 and 60 amp fuse would correspond to each pole of the breaker. I cleaned up the wiring with new 10guage. It has a 40amp contactor for the elements and fan. It threw the breaker yesterday after running for a week. The main questions...do I need a 50amp contactor, what one did you use above, the Honeywell is $100 and maybe overpriced....Or does this sound like a wiring issue, I duplicated the previous wiring but that doesn't mean it was wired correctly in the first place. Thank you, and yes I will contact a tech if you think it is a wiring issue.
Your contactor is probably a bit small. 50 would be better. The Honeywell contactor is used because it is quiet operating. Any contactor with the rating will work.
Do you have just a single 50 amp breaker in the panel for your furnace or are there 2?
GFM
50 amp breaker ????? U need 60 and a 30 or a 70 amp breaker with minimum number 4 wire or 60 Amp with number 6 and 30 amp with number 10 wire
Thanks for the video GFM. Two quick questions:
1. Why did you choose a two pole contactor over a three pole?
2. Whats the reasoning behind two number 10 gauge wires from the contactor rather then one heavier gauge wire? I assume all you had was number 10 wire and thus just doubled it.
Just looking to learn.
PHC Apprentice If your furnace had more elements, you could use a 3 pole. This one had 4 elements. The #10 wire is used for each element, as each element is 5000 watts or 20+ amps. Hope this helps.GFM
Thanks gfm!
Hmmm... my furnace states the breakers on it, is for short circuit only and not for overload. But then both breakers are 60 amp. Interesting, I'm learning from your videos on furnaces, after watching this video I now know my furnace does not have sequencers. Lol since I bought this furnace I thought it did... it all makes sense now why all my elements were kicking in at once. I kept thinking what the???... little did I know. Thanks, you just answered a question I had asked myself 100 times. PS, furnace guy, you really thing contactors are better than sequencers?... just askin, it seems like it would cause a furnace to use more electricity over time???
How would you this effect an eco motor
It should work normally.
GFM
Like your idea of contactor. Is there a way to simply check the voltage across the sequencer itself while installed to tell if its bad?
If you test across the contacts during a call for heat, after enough time has passed for the sequencer to close, you should read 0 volts. 240 volts means the contacts have no closed.
GFM
Can you draw a wiring diagram of this? That would be most helpful! Thanks, Tom
I'm currently working on this same style furnace the issue is the blower won't shut off after the thermostat is satisfied could this be the contactor is bad ?
You probably have a wiring problem.
GFM
If you are going to use a contactor, use a 3 pole contactor ( one per element). It is not a good idea to double lug and you will reduce the load on the contacts.
You could certainly do that, but if your contactor is rated for the amp draw used, there is no overload. Contactors are commonly double lugged in the industry.
GFM
3 pole contactor I see on 3 phase but not much on single phase due to economic issues
So the amp rate on contactor is for each lead? Thank you
Yes, a 50 amp contactor can operate 4, 25 amp elements.
GFM
What type of wire and size wire are the wires going to the sequencers and limit switches?
+SombraLocs I always used 105 degrees C #10.
GFM
thanks Gary, need some advice i have a question maybe you can help. i'm up north, first freezing cold spell since the winter, first time aux heat strips in use in the air handler since winter (Trane 4tee3f37b1000aa). When the aux heat starts, there's a machine gun rapid fire/chatter sound at the air handler, right about where the 20KW line comes in. pretty loud i'm not really familiar with relays or contactors but could it be relays that turn the strips on and off that can make the noise?? Once the heat gets going and the fan is up to speed, noise stops, and then starts again a bit when the heat cycle shuts off. I'm still getting aux heat and the fan is running smoothly and is set to ON, outdoor HP heating fine otherwise. I'm DIY have changed blower motor module and capacitors but no relays. system is 12 years old. 1 have 4 heat strips x 5kw each
The chattering indicates the control circuit has excessive impedance. The coils of the contactors are not getting enough power. The first thing I would be looking at is the thermostat.
GFM
@@grayfurnaceman thanks for the quick reply Gary. From the tstat display everything looks normal. Can you suggest specific troubleshooting steps- what I should be doing/looking for inside the air handler? do you mean that the control signal from the tstat is only opening the circuit partially at the heat strips and what might be failing exactly to cause this (relay/contactor/sequencer?), does that indicate mechanical failure/physically damaged/burnt parts (what and where), and/or loose wires or connections? or more like a board? I'm not that familiar with electrical but i can methodically identify specs and replace parts and reconnect wires based on existing config. my budget is very limited so i need to figure this out myself like in the past. sorry for the long question.
@@soneeeee4440 My thoughts are that the thermostat may not be operating normally and will be not transferring power to the contactors.
GFM
Do you have a part number for a 3 pole contactor? Does the contactors turn on and off from the 24 vac directly from the thermostat? I didn't see you show that part.
Any 50 amp contactor with a 24 volt coil will do. The thermostat energizes the contactor coil.
GFM
My only concern is the UL rating. Once you change things around it is your design. It clearly works better, but could it make you liable?
dpeagles I guess the point is, what is more important, whether it works well or whether is passes UL. I guess its up to the individual technician. Thanks for the thoughts.GFM
Since there are also 60 & 30 amp breakers at the main panel, if the 30amp here in the air handler is bad, why can I not just bypass the breaker in order to get them up & running quickly? It still has the 30amp at the main for circuit protection. Nearly all brands do not even have breakers at the air handler. Nordyne does it this way though and not sure why.
Here is the problem with bypassing the breaker. Because the manufacturer installed it. Its that simple. You are correct, the circuit protection is still there. However, if there was a fire, you would be blamed. Even if your actions had nothing to do with the fire.
GFM
What is cause the a made the wire burn 🔥 up and don't make the brake pop 🤔
ok i did it but i had to put all 3 elements on the 60 and the fan and transformer on the 30 or the breaker kicks out on the 30 it is working now is that ok i changed all 3spring elements and limit switch
+scotty dog If it immediately kicks off, look to your wiring. If it kicks off after some time, be sure the terminals at the breaker are tight and check amp draw of the circuit. I have done this dozens of times. It works well. Also, if you put 3 breakers on one 60 amp breaker, the breaker will kick off after some time.
GFM
I notice the amps were above 60 wont that blow the 60amp breaker when the furnace fires up?
+Jeff Booher The meter is measuring the amp draw of both the 30 amp and the 60 amp breaker. So it would need over 90 amps to kick the breaker.
GFM
A relay (contactor) is simpler. I guess the only downside is the possibility of noticing the lights blink when all three loads come on at the same time.
That has been the argument against the use of contactors for over 50 years. I would say that may have been true when the grid did not have the capacity it does now.
I have not seen that issue happen for many years.
GFM
Hey watch out, our grid has a rating of D+.
. I have a Good man electric heater and a serviceman said it need a control panel but when I call another company i the deal with electric heaters they mention that it need a Heat strip.. *The heater won't come on so I'm wondering just from hearing about the heater won't come on,( The blower comes on) but there's no heat what would you suggest,?
Usually these units have several heat strips. If one has failed, you should still have some some heat. It sounds to me that neither one has done a complete diagnosis.
GFM
Gary, what amp size is the contactor in this video?
Its a 50 amp resistive.
GFM
I live in a rural area now and although my panel specifies using 105C wire only it is unavailable unless I want to drive about 60 miles. Is there any practical reason not to use thhn/thwn2 ?
You can use THHN. Just be sure the connections are tight and if it is using #12 wire,, use #10.
GFM
@@grayfurnaceman thanks.
How do you determine that a 50 amp contactor can handle four 25 amp elements? I guess it makes sense, as that’s two 25 amp elements per side…
You got it.
GFM
I am having a problem where the fans will not cut on by the thermostat but will cut on my the fan switch. I had the same issue with the burnt limit switch could the problem be the sequencer?
You could have a sequencer problem or a burned wire to the fan.
GFM
U could also use 2 contactors and a delay on make timer. P.S. your not using your crimpers correctly. your getting a hole because that's for non insulated connectors. go all the way to the bottom. that's for insulated connectors. good video though
Hi, how do you calculate what size contactor to use to replace the sequencer [examaple amps] THANKS FRIEND
Using the amp draw of the elements and motor and matching the contactor to it. Example: 20 amp element, 5 amp fan, 30 amp contactor.
GFM
Thanks
How much of a local brown out will this cause? Over time, modern electronics are extremely vulnerable to brown outs that aren't even noticable visually.
I have not seen any problems with this type of repair. Some manufacturers equip their furnaces with contactors.
GFM
One question I have is if your using a 50 contractor and your pulling 65 amps total. Why is this contractor not to small. Is it because each side of the contractor can handle 50 since it's a double poll.
Yes. Each set of contacts can handle 50 amps.
GFM
I am thinking about replacing my sequencers with a CONTACTOR. I would like to know if my furnace also has Air Conditioning if this is a cause for concern?
The only problem I can think of is the fan relay must separate the elements from the fan when cooling is energized.
GFM
@@grayfurnaceman Thanks for the quick reply. I ALWAYS have my fan on at all times. So I will wire it on (thermostat FAN on switch). That should work fine, your thoughts?
It should.
GFM
@@electriccar3253 Thanks
Received my Honeywell contactor today. Where can I get 10awg wire??? I went to 4 different hardware stores and they don't sell "stranded" 10 gauge. Could you point me in the right direction please. I will get it online but would like to know brand type etc. Thank you very much if you could help me with this.
Was the contactor rated at 50 amps? The amp draw was 65 amps.
+KEITHS AC the total amp draw was for both legs you can run 50 amp on each leg so he ran 40 amp on one leg and 20 amp on the other leg
I think the breaker is rated for 50 amps period not each leg or terminal. Cannot put 50 amps on one leg than 20amps on the other. On a regular breaker if using for heaters you half to depreciate the breaker by 80% example 80% of 50= 40amps
can you seen me a wiring diagram of how you wired up contactor
No diagram needed. You put the wires exactly the same as they are on the sequencer. I mean it is exactly the same
I have a quick question i hope you can help me confirm an issue with my furnace. The fan kicks on when the thermostat is off. I know the thermostat is good. The fan kicks on for 10-15 minutes several times a day. Control board issue? Is this normal? Any help would go along way. Many thanks!
arcdraw Is yours an electric furnace?
GFM
No it's a gas furnace. I've narrowed down the issue to the thermostat. I've been able to check the board and it all looks good.
+arcdraw your limit is breaking on your gas furnace not enough airflow through the heat exchanger or heat strips are overheating due to covered in grime
So the question I have is the sequencer has a purpose to run the fan after the strips shut off. The question is how efficient is this do the limits pop a lot or do you tell the customer to leave fan to on in the thermostat switch? How many call backs do you have once a year once in 2 years just curious not trying to bust your balls.
+andy sharp The sequence of the electric furnace is to start one element and the fan first. The other elements sequence on some seconds later. When the thermostat is satisfied, the elements shut down in the opposite sequence with the last element shutting down as the furnace fan shuts off. The fan normally does not run after the last element shuts down. Leaving the fan on is not necessary. Efficiency of the electric furnace is essentially 100% as there is no stack loss. Callback ratio for me was around 3%. Hope this helps.
GFM
Basically I'm trying to round up the parts to save money then I'll call in a professional to wire it ... it has been difficult acquiring these contactors I don't care about the noise what was the model used in this video? I have a 5 element furnace so I like the idea of adding a second contactor and installing a inline time delay device any help would save my family money would be great
It would cost you money in the long run don't do it !!!
I have had this in place for a year ... noted no extra cost and after years of a broken furnace it works fine...
I also have a five element furnace....
The contactors should be available from any electric supply house. 50 amp resistive contacts, 24 volt coil. The contactor used for the single element is a 30 amp resistive 24 volt coil. I don't see the need for the time delay.
GFM
I just did this to my heating system I plan on doing a heating test it will take 9 heat ups and see how much time time and wattage to heat it up in the following configs 5KW at fan speeds low med and high 10KW low med and hi and 15KW low med and hi and I'll calc the data and make a graph give me a few weeks....
Why not use a 3 pole contactor? Less confusing, although more expensive.
You can use a 3 pole.
GFM
Won't it pull too much amperage when it closes?
It does not. Several furnace manufacturers use contactors in their furnaces.
The reason for sequencers to reduce initial amp draw came from the 1960s. At that time there were many pole transformers that were not designed for those high loads. That time has passed.
GFM
GFM good video. I am not a big fan of the heat sequencer
the amperage went up to 68 amps , and the contactor is rated to 50 only eventually the contactor is going to get burnt sooner , they are taking too much heat
The contactor is rated at 50 amps per pole. The original clamp was around all 3 element wires. You could run up to 100 amps thru both poles of the circuit.
GFM
I have 5 elements I will ask the service tech to install 2- 50 amp contactors 1- 50 amp contactor for two elements1- 50 amp for three elements 1- 25 amp contactor for the blower?
+Jeff Booher One 50 amp contactor will operate 4 elements breaking one side of line. The first element and the fan can be operated by one 25 amp contactor. If you want to separate the fan from the first element, you can use one pole for each. Hope this helps.
GFM
I would love to see a 30 kw ( not uncommon where i live) done this way,and not have the lights dim!!!!!!!!!!
And if a fire happened and this was found your insurance would not cover you.
I have done it and the lights do not dim. The sequencers were designed to be used when pole transformers were not designed for the high loads we have now. They pretty much stopped using the smaller transformers in the 1970s.
GFM
None the less you are altering or eliminating the factories control features and in my country you are not allowed to do so ,without the governing authorities permission so stop showing people how to do stupid things...just fix it properly and it will last another 20 years.
Ohh that right 3rd world country where your power browns out a lot... gotcha.. Also he did say this is for HVAC techs not general public....
Hi. I’ve heard this statement about transformer load and sequencers before.
Perhaps you could explain to me how a sequencer lessens the load on your transformer.
I can’t wrap my head around it.
It makes no logical sense to me.
If my furnace draws a 100 amps. It going to draw that same amount with or without it sequencers.
Thank You
De-rats-nest-ing - Bravo!
I was wondering I had havc guy HV AC guy come in here and my control board is burn up and he replaced it with a contactor but he didn't hook up the emergency heat my question is how does that work where those low voltage wires hook up to
That is field installed wiring so there is no set method. About all I can say is the emergency heat is connected to the coil of the contactor.
GFM
with me, i think the way you replace sequence by compressor contactor not a good idea. if you do so when call for heat, too much power go to all 3 heating elements at the same time, making breaker shut off easily
Electric elements have no inrush of power, so they will not kick off a breaker. Note also that Trane heat strips all use contactors to control the heat strips. The idea that turning on all strips at once will brown out the circuit is a myth.
GFM
Proper electrical design requires the breaker load be approximately 80% or less. Given typical 5kw elements draw 20 amps each, then the breakers have amp headroom. Remember sequencers end up running all elements at once for long periods during cold weather. The key is proper breaker and wire sizing which is a constant either way. Finally the inrush to worry about is the AC compressor, often exceeding 130 amps on startup even though the breaker size is 30 or 40 amps. Breakers have thermal delays to accommodate large initial inductive (motor) loads.
The point was if you think heat strip inrush is a problem then you really can't sleep nights knowing about the compressor's breaker inrush current.
dont remove the sequencers,, they bring the heat up in stages and then down in stages , which provides a nice gentle heat,,,and also the fan is to run after the heat is off to blow the residual heat out of the plenum.. ,, this is a dangerous video.
Sequencers do bring up the heat in stages, originally to ease load on pole transformers when these transformers were sized smaller. That need is no longer there.
Most sequencers have a life span of 1/5th that of contactors. I cut my teeth on these things and after replacing them sometimes every 2 years, found that Honeywell made quiet operating contactors for just this application.
Heating elements have virtually no thermal mass and all the heat is removed by the slowing fan.
There is no such thing as gentle heat. All elements coming on at the same time preheats the duct work to reduce cold air on startup.
Some manufacturers (such as Trane)use contactors for all their electric heat strips. So much for the dangerous video.
GFM
Some r made to work with contactors so there is no problem . l wiil instead said becareful . with safety heat sensor
It ‘s not good for energy efficiency.
Using a contactor to immediately energize the elements will have no effect on energy efficiency. When the elements are turned on, they are on and using energy. There is virtually no thermal mass in the elements. When they go off they are off. The energy is off. The heat is gone. Sequencing elements on and off was originally used because the pole transformers were not capable of accepting large loads all at once. Modern transformers are easily capable of handling this load.
GFM
If it pure electrical heater may not much difference . If use with heat pump as auxiliary heat , auxiliary heat may not need to turn on all before return to regular heat (coil).the less auxiliary heat been used ,the less energy consumption.
definitely not a do-it-yourselfer job someone can get seriously injured
sequencers suck so cheap
That is the reason for the video.
GFM