No heat from strips (emergency/aux heat) after new sequencer

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Old 11-13-18, 08:10 PM
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No heat from strips (emergency/aux heat) after new sequencer

First of all, I am a novice. Please forgive my limited understanding. However, I have been researching my issue for the past week or so. I thought I found the issue of my weak heat (the sequencer), but after install of a new sequencer today, I am not so sure.

The issue: heat pump heat works, but cannot heat the house adequately on colder nights/days. In emergency heat mode, heat does not increase but the fan kicks on as normal. Weak heat from pump only. This is a dual heat strip system, two 5kw for 10kw total.

I figured it was the heat strips not turning on. First, I checked all the connections of the wires to the sequencer and temp limiters. I turned the system back on, and to my surprise, I had very hot (100+f) air from vents. I was so happy because I thought it was just a loose connection somewhere. However, when I turned off the system at the thermostat, nothing happened, the heat and fan stayed on even in off position. A quick tap with a handle of a driver to the sequencer shut it off (like fonzie).

I thought, of course, the sequencer was bad. I ordered a new one and installed it today. However, now it has returned to the original state, weak heat without strips turning on. I triple-checked all connections are the same as before and am confident about that.

Trying to test the new sequencer, I got a multimeter at my local hardware store, although, I don't really know what I'm doing. When testing the new sequencer, the back two connector terminals, my multimeter beeps, indicating an open circuit (I think?). Is this normal? I watched a video of someone testing a sequencer and they knew it was bad when it beeped.

I am sorry for the long post and lack of knowledge, thank you for reading. Could anyone help me to determine if, in fact, my new sequencer is bad? I was pretty sure the symptoms before indicated it was bad. But the wiring must be correct because the heat strips kicked on before. Is there anything else I can try?

Here are photos:

1) The broken sequencer, which worked (stuck open heat), and fell apart when I took it out.

2) New sequencer installed, but not turning on heat strips and multimeter beeps when connecting top and bottom back (gold) terminals
 
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Last edited by AoyamaJPN; 11-13-18 at 08:31 PM.
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Old 11-14-18, 06:26 AM
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This threads unit is exactly like mine. https://www.doityourself.com/forum/heat-pumps-electric-home-heating/537095-heater-does-not-work-ac-fan-do.html

I do not think I have 24v at the sequencer when the unit is on and in emergency heat mode. I tried (carefully) to use the multimeter at the two back terminals (orange and violet). Is there any way to jump the heat strips for testing?

Thank you!
 
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Old 11-14-18, 09:56 AM
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Welcome to the forums.

A few more pictures with one further out would be helpful.
A wiring diagram would be helpful too or a model number of that unit.
 
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Old 11-14-18, 10:15 AM
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PJmax, thanks for your reply, I really appreciate it! I am attaching the wire diagram, which I can't understand, from my new sequencer. The unit itself is KFAEH0401N10. I also attached a photo from further out.

I admit, I spent most of the night trying to troubleshoot this to keep my family warm. I think the sequencer is most likely good, but perhaps not getting 24v to it. Which may be why the broken sequencer kinda worked (even though it may not have been getting 24v, though it stayed stuck on until breaker was off or tapped directly).

Now, I am trying to figure out how to test if 24v is getting to the sequencer. I used my multimeter with the unit on emergency heat and touching the leads from orange to purple showed 0v. Is there a way to jump the sequencer? Or, perhaps at the thermostat?
 
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Old 11-14-18, 10:25 AM
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Please download the manual in the link below.
Your unit should be diagram 1..... approx page 5.

Manual

It looks like there is orange and violet used for 24vAC to the sequencer. The orange shows as common. That means you can connect the violet wire to R to activate the sequencer.

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Old 11-14-18, 10:55 AM
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Thanks again, PJmax. I apologize for such a silly question, but do you mean attach violet to red at the thermostat or at the unit itself? The violet wire at the sequencer goes straight into a plug to the control board, so there does not appear to be a way to connect it to an existing red wire. Would you mind elaborating on the "connect violet to R" to activate the sequencer (manually and temporarily I presume)? Thanks so much, and pardon my ignorance, I am learning and brand new at all of this.
 
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Old 11-14-18, 11:00 AM
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If you look at my diagram..... the orange wire from the seq. is connected thru the plug.... changes to brown and then goes to Common.

The purple wire from the seq. goes thru the plug.... and changes to white. This white wire is where your thermostat connects. This white wire will activate the seq. when it sees 24Vac. If you don't have 24vAC on the white wire on a call for heat...... disconnect it from the thermostat cable and connect it to the red/R wire. See if that activates the heat.
 
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Old 11-14-18, 10:14 PM
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PJmax, thank you again. Your explanation of the diagram below makes sense. However, unfortunately, when white and red wires are jumped at the thermostat, the heat strips are not activated. I've taken a picture before connecting the white wire to the red terminal. It looks like blue and brown are not used. Also, it looks like white wire should be jumped to "E" as well as "AUX". I also tried that, but to no avail.

Is there anything else I can try? Do the wires look to be connected to the correct place?

It's so strange because I know the heat strips work. Ironically, when the old sequencer was broken, it was stuck on and I was getting 100+F at the vents. Now, with heat pump it's more like 80F. I don't know what to do, and I can't afford a professional at the moment.

Thank you again for all your help!
 
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Old 11-14-18, 11:41 PM
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When you connected the white to the red wire....... did you get 24vAC on the seq. coil (yellow and purple) ?
That's what we are aiming for.
Try connecting the white to red right at the air handler.

Your stat wiring looks correct.
You can add a jumper from E to AUX for emergency heat but that is not the current problem.
 
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Old 11-15-18, 06:36 AM
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PJmax, here's what I did:

1) Connected white to Rc at the thermostat (R and Rc have jumper)
2) Turned breaker on and called for heat
2) Touched multimeter (switched to volts) to orange and purple
3) Measured 0 volts

Is there a safer way to do this? it's cramped in there and touched the orange a purple connectors a few time to make sure it was, in fact, 0 volts. In the process, I must have slipped a bit and arched over, spark and loud pop from the orange lead which scared me a bit (and actually left a mark on the orange wire). I am almost ready to give up and call someone. But I feel like I am so close and need every bit of cash I can save for the holidays.

Again, thank you so much for your help and patience.
 
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Last edited by PJmax; 11-15-18 at 03:20 PM. Reason: added wiring pic
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Old 11-15-18, 03:22 PM
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I enlarged the wiring junction box. That's where we need to focus. Your thermostat cable should be there as well as a second cable to the outside condenser. For some reason..... it looks like the white wire isn't connected. Is that correct ?

Try to gently pull the wires out of there and shoot me a closeup picture.
 
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Old 11-15-18, 05:53 PM
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PJmax, YES! The white wire was not connected. It looked like the end was never stripped. I connected it to W3 as W2 was taken by black, but AUX is still not kicking on when called by thermostat. Can you make sense of any my photos? What should go where here? Thank you so much! We are close...
 
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Old 11-15-18, 06:05 PM
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I labeled your picture. I'm pretty sure I labeled the picture correctly. The white wire of the thermostat cable is the one that needs to be connected to W or W2. I don't think W3 is active on that unit.

I'd connect both white wires to W or W2.
 
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Old 11-15-18, 06:30 PM
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I think I just created a bigger problem. I connected the white thermostat wire to W2 (no plain W, just W2 and W3). But, I left the black wire attached to W2 (so, white and black together). It kicked on for a minute then fan shut off. I disconnected the white thermo wire from W2 and left it as it was (no white wires attached). But now, the unit will not kick on the fan no matter what. I did notice a light smell, but it could be from before this incident. Any help greatly appreciated!
 
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Old 11-15-18, 06:41 PM
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I have double checked everything. Heat pump outside and fan inside the garage unit will not turn on at all. I checked the fuse on the main board, and it looks good. Now, I need to focus on getting heat pump heat back, no heat at at all would be a bad thing. Any help greatly appreciated! What could I have blown by connecting the black already at W2 and the white?
 

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Old 11-15-18, 07:03 PM
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That 5A fuse on the board probably burned open.
 
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Old 11-15-18, 07:14 PM
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Original fuse looked OK. But, I had a new 5a fuse lying around, so I replaced it. Still, heat pump and furnace fan will not turn on. I also went outside and flipped the breaker at the pump just in case. Where do I go from here? New control board?
 
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Old 11-15-18, 07:50 PM
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There really isn't a control board in them.

Check for 24vAC from the R to the C terminal. If it's not there.... check the transformer. There should be four wires on it. Two are 240v in and two are 24vAC out. Check for the 24vAC.
 
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Old 11-15-18, 08:09 PM
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Is it this (see attached photo). there are five wires. could you elaborate slightly how to test for 24vAC? unplug two ends from the board and test those ends? or, need to test them inside somehow while connected? thanks again for your support. gonna be a cold night...

also worth noting this transformer looks tired and has a greasy substance on it?
 
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Old 11-15-18, 08:26 PM
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looks like 0v from out side?
 
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Old 11-15-18, 08:30 PM
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Looks like it's dead. The home improvement stores should have them.
Make sure it's 240v x 24vac. 40va. Change that fuse to a 4A one also.
 
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Old 11-16-18, 03:23 PM
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I ordered a new transformer from Amazon. No one local had one, and the HVAC retailers wouldn't sell me one.

In any case, should I remove the black wire from W2 and replace it with white? What does the black wire go to perhaps?
 
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Old 11-16-18, 03:43 PM
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In know my depot and lowes stock those transformers..... or at least I've seen them in both stores recently.

I don't know what black is connected to. Based on your stat wiring..... this is what you should have....

COLOR ........ STAT ........ AIR HANDLER ....... COND
White ---------- Aux -------------- W2 ----------- outside condenser - electric heat
Green ---------- G ------------------- G -blower
Orange ------- O/B ----------------- O ---------- outside condenser - heat or cool mode
Yellow --------- Y -------------------- Y ---------- outside condenser - contactor
Red ------------ R -------------------- R ---------- outside condenser - 24vAC to defrost board
-------------------------------------------C ---------- outside condenser - C or common to defrost board

I see a brown to brown connection at the air handler but nothing to the thermostat. That may be C.
The white wire when active turns on the electric heat. It also connects to the outside condenser so that when in defrost mode.... the electric heat turns on.

These are the minimum colors/wires required.
At your stat I see blue and black not connected so those are spares.
 
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Old 11-17-18, 06:40 AM
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Here's and update...

I got a new transformer locally at an electronics store. No local HVAC would sell me one and said I had to make a service call, even though they had one on each truck. In any case, I got a new one and I mapped to the old transformer wires and matched them to the voltages of the new transformer. The old transformer had 208, 230, and one "OV" (black). The new transformer had 208, 240, 120 (black) , and Com (white). I had to guess between white and black on the new tranformer. I guessed black (120) went to what was labeled "OV" on the old. Big mistake. Shortly after I turned the breaker on, smoke and pop from the new transformer.

I called an electrician. He had a trasformer on his truck. I told him the entire story. He said the way the transformer was connected to the board previously was incorrect. He could tell the wires were cut previously and hacked together. Some we're so short he said the previous person obviously couldn't find the right configuration and had to cut several times.

His transformer hooked up in a new way to the board now allows the fan to kick on and heat pump heat, great news for my family, but I paid a service call plus a tripple than online cost for the transformer.

He could not figure out why the heat strips would not kick on. We replaced white with brown, etc. The board blew 5a fuses each time. He put a theromother probe in the air vent directly at the handler when he changed a few things, but nothing kicked on the strips.

He said he could not help unless I have a diagram of the ICM 272 board. I showed him what was online, but he said it didn't help him because it was labeled the same as the board. I remember I also had page 5 for the KFAE unit, but he said it would have to be another service call to troubleshoot at a later time.

All that said, still no Aux heat. Any advice for next steps? I do not want to blow another transformer troubleshooting and have no heat. Any safe way to proceed, or should I throw in the towel and pay for professional to troubleshoot as it appears to be complicated even for them?

Thank you so much PJMax, regardless, I learned a lot through this journey and that is valuable to me.
 
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Old 11-17-18, 03:48 PM
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Make sure it's 240v x 24vac. 40va.
That's why I posted this in my previous reply.

Go back to post 12. I labeled your cables. Unwrap that white wire from the stat cable. Connect your voltmeter to that white wire and either the C terminal or the metal frame. We need to get 24vAC on that wire when the stat is calling for electric heating. Once we determine that wire is working normally we can check the sequencer.
 
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Old 11-19-18, 08:53 AM
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PJmax, yes, I got a 240v, 24vac, 40va transformer (two, technically). And, an update, the (second) transformer the professional installed burnt out about 24 hours later. Now, I have no heat at all, again. No power to the unit or heat pump.

I understand your instructions to map out the aux heat wires, however, I must get the unit powering on and have heat pump heat in my house before moving on.

So, now, I need to confirm the correct way to wire a transformer for a KFAEH0401N10 hooked to a ICM272 board. I have diagrams for both, but I am not very good at reading them.

http://www.icmcontrols.com/ProdImages/ag-LII102-2.pdf. On this diagram, the professional hooked up the 240v line to the "240VAC" section of the board. However, this was not how it was hooked up before. It was hooked up to the "AC Transformer Line" to T3. This is the way I hooked up my new transformer and it blew. Professional installed to "240VAC" section worked for almost a day though.

Unfortunately, I am out my service call fee for him to install it incorrectly. I am thinking of ordering another transformer. https://www.amazon.com/Packard-Contr...4v+transformer. In this case, red and green go to the same 24v places on the board as before "R" and "C". I got that. Would the orange wire go to T3 on the ICM272 board (link to diagram above)? What would go to T1 and T2 (Dummy). The old transformer that lasted for years was hooked up to T1,T2,and T3, but the part itself doesn't have a map of what wire was what.

Thanks again,
 
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Old 11-19-18, 09:14 AM
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Ultimately you need to get a fuseholder to put in the 24v line to protect the transformer.

It sounds like that tech did not use the proper high voltage taps on the transformer. You need to use the neutral and the 240v tap. Any extras need to be capped off. The three taps (T) are neutral, 208v and 240v. I don't know which is which. You have a meter...... it will most likely be T1 and T3. Check for 240vAC on the terminals. The transformer can be connected to any 240v source in the unit.
 
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Old 11-20-18, 10:11 AM
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Does it matter which (of the two) 24v lines I put the inline fuse in (R) or (C) on the board? What fuse amperage would you recommend? 4 nights now with no heat and freezing temps has not been fun. The HVAC "professional" electrician convinced me to buy a new control board, but that won't be here until Monday. I also think he installed the transformer incorrectly. I will buy one local today (along with an inline fuse) and install it the way the old one was, as I noted everything (T1 netural, T3 240v). T2 is labeled "dummy" on the board, the old transformer has the 208v line there, but I guess that's not used. Thanks again for all your help!
 
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Old 11-20-18, 08:40 PM
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A fuseholder would go in one of the two 24v transformer wires. It doesn't matter which one. I'd use an ATC-4 fuse and fuseholder. Any auto parts store would have both.

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Old 11-20-18, 11:12 PM
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I was able to get a fuse holder. I put it on the new transformer 24v side wire to R on the board. The other 24v wire went to C on the ICM272 board. T1 went to the neutral wire and T3 to 240v wire. I only had a 3amp fuse, so far it's been running for an hour and not blown. I think the other transformer was put in incorrectly by the electrician (240v section on the ICM272 board). I will keep it running tonight. If the fuse doesn't blow, I'll continue on to troubleshooting aux heat.
 
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Old 11-21-18, 09:29 AM
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A 3A fuse is also ok. Sometimes it can be a little on the small size depending on load.
A 5A fuse as usually recommended but will not always protect a transformer..... so I don't recommend using a 5A.
 
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