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Discussion Starter · #1 ·
Hi, i have a ICP Electric Furnace Model: MF20N2600A1 along with a HEIL Heat Pump Model: CH5548VKD1, YJ048GB1. This was already installed in a house i recently bought and at first, i replaced the 1085928 fan control board because it had a burned and cracked chip on it and it smelled roasted so i replaced it with an aftermarket one and it burned the same way after 3 weeks of light use. So i bought another one on eBay, this time and OEM one, used but i installed it and it worked for 3 months, i had AC cooling my house very well, but yesterday, the thermostat went blank and i already knew the board got fried again. So i opened the unit and again, the board is fried the same way, the chip is cracked and smells roasted.

I tried to find something about this electric furnace on the internet, but no luck, nothing about this ICP unit or why does this board fry itself in the OFF position..

Here are few pics of my issue:








I have a Honeywell CT3611R4450 thermostat that was in the house. I'm thinking it's the thermostat that might be causing the boards to fry or i dont know what. Any help would be greatly appreciated as i would like to use the heat pump in the winter.
 

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Hi, i have a ICP Electric Furnace Model: MF20N2600A1 along with a HEIL Heat Pump Model: CH5548VKD1, YJ048GB1. This was already installed in a house i recently bought and at first, i replaced the 1085928 fan control board because it had a burned and cracked chip on it and it smelled roasted so i replaced it with an aftermarket one and it burned the same way after 3 weeks of light use. So i bought another one on eBay, this time and OEM one, used but i installed it and it worked for 3 months, i had AC cooling my house very well, but yesterday, the thermostat went blank and i already knew the board got fried again. So i opened the unit and again, the board is fried the same way, the chip is cracked and smells roasted.

I tried to find something about this electric furnace on the internet, but no luck, nothing about this ICP unit or why does this board fry itself in the OFF position..

Here are few pics of my issue:








I have a Honeywell CT3611R4450 thermostat that was in the house. I'm thinking it's the thermostat that might be causing the boards to fry or i dont know what. Any help would be greatly appreciated as i would like to use the heat pump in the winter.
Its a defect in the board or an unusual secondary xfmr spike.

(The only thing that throws me is with a low voltage condition i.e shorting to ground, loose connection, the fuse on the board should have blown).

Did the fuse blow?

Check to make sure there is nothing conductive touching the back of the board.

C
 

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Discussion Starter · #3 ·
Both boards had blown fuses. There are no wires touching the board and the board is attached to the unit securely. I am thinking that the thermostat is doing something wrong. I still have to check the wiring at the heat pump, maybe there is something wrong? But why would one board work a week and the next almost 3 months..?

Can i use a different, cheaper more reliable board for this HVAC unit or am i stuck with this pile of junk in my attic?
Thanks!
 

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Both boards had blown fuses. There are no wires touching the board and the board is attached to the unit securely. I am thinking that the thermostat is doing something wrong. I still have to check the wiring at the heat pump, maybe there is something wrong? But why would one board work a week and the next almost 3 months..?

Can i use a different, cheaper more reliable board for this HVAC unit or am i stuck with this pile of junk in my attic?
Thanks!
Is the board touching the metal plate that the board is mounted to that is mounted to the front of the blower?

It is probably best to stick with that Texas Instruments board, but you may be able to retrofit with another board (you'll have to ask a service tech.)
 

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Discussion Starter · #5 ·
Is the board touching the metal plate that the board is mounted to that is mounted to the front of the blower?

It is probably best to stick with that Texas Instruments board, but you may be able to retrofit with another board (you'll have to ask a service tech.)
Of course not, the board is mounted on its 4 plastic stands.. if it was mounted on the bare metal, the whole unit would catch fire...

Texas or non texas, 3 boards burned up.
 

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Good. I know it is mounted on 4 plastic stands, but sometimes the board can come in contact with the metal mounting plate.

If it did touch the metal, the whole unit shouldn't catch on fire. It might ground out the control board and cause it to get hot, start smoking, or the board catch on fire, but unit itself wouldn't catch on fire. Plus, the fuse on the CB should blow before it got that bad.
 

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Discussion Starter · #7 · (Edited)
I have one board that has a smoked IC chip and when i install it, put a new 5amp fuse and turn the power on, the blower fan turns on and stays on and the unit cools, but the fan doesnt turn off. The board looks liker it shouldnt work, but it somehow does. The rest are completely dead.

The way it happens is the unit works fine, then next morning you go to the t-stat and it's blank, dead.

The fuses were all blown and so were the IC chips. All boards were properly mounted on their plastic post clips and none came loose. Its either the thermostat is causing something wrong or i have a a-hole rodent that likes to bite the t-stat wires from time to time and burn out my boards...

I wish i could sub this $125 board for a cheaper trane or similar board for half the price, then i wouldnt worry about it burning up, i would buy 5 in advance and be happy...

Another lesson learned, never buy a house that has a ICP central HVAC! :furious:
 

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1) check ALL the connections in the plastic molex plug connectors with a magnifying glass. one pin may be backed out and a poor connection causing over amping may be happening. or they are corroded.
2) check the amps draw of the unit before it enters and with the fan running and fan door on. compare it to the specs on the rating plate. looks like an over amping/high current draw or low voltage problem 2 me. check the incoming voltage and wiring connections where they enter the unit. they can get loose or corroded and hopefully U have no aluminum wiring in the house. check the connections at the panel for tightness also. check the unit grounding to a water pipe with a cheater wire, should have 0 or very low reading. poor grounding can fry boards.
3) check your fan motor capacitor as it may be getting weak and overamping the motor. need a microfarad reading meter. check the motor after running it for 15 mins. if it is so hot you cannot touch it then it may be seizing and overamping.

Good luck
 

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Discussion Starter · #10 ·
Ok! i'll buy one more board and run those tests, thanks all for your input. Too bad you didnt see this post earlier, i wouldn't have to sleep naked with fans on throughout those hot and humid nights..

Yuri, explain to me about that 'cheater wire' thing please, thanks!
 

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The only way to really know if you have a true proper ground to the unit is to check for ground between it's ground connection/wire and a copper water pipe or obviously the ground in the panel or to the house .

Batman: How do you get to a water pipe if it is 20 feet away ????

Answer: Robin

You take a piece of any kind of wire (#18 gauge minimum and hook it up to said water pipe and snake it back close to the unit and then use an ohmmeter. Pain in the butt but it works. If you don't have a good ground then you need to find out why and yes it does blow boards.
 

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Ok! i'll buy one more board and run those tests, thanks all for your input. Too bad you didnt see this post earlier, i wouldn't have to sleep naked with fans on throughout those hot and humid nights.. EWW, too much information:laughing:

Yuri, explain to me about that 'cheater wire' thing please, thanks!

.....
 

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Discussion Starter · #13 ·
i see what you mean, i'll check the grounds of the house, but what still confuses me is the fact that 1 board worked 10 days, another about 20 and the 3rd one worked almost 3 months. They all went out the same way, smoked IC chip..
The one that worked the longest was an original OEM board from the same unit that i bought on eBay. I assume those clones these days are a lot cheaper quality and dont hold that well..
 

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grounding is like VooDoo theory. you may have an intermittent ground due to poor connections at the board or all the rest of my scenarios. problems like yours are the WORST but after many yrs of experience and misery you learn a few tricks.:laughing:
 

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grounding is like VooDoo theory. you may have an intermittent ground due to poor connections at the board or all the rest of my scenarios. problems like yours are the WORST but after many yrs of experience and misery you learn a few tricks.:laughing:
I realize your arrogance and wisdom but, the EASIEST way to check for a proper ground is to check voltage on incoming power to ground THEN check for continuity between ground and the bonding of the secondary side of your transformer.

Running to a copper pipe is no guarantee that the pipe has even been bonded to the GEC, especially if someone has replaced some of the copper for plastic.
 

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Arrogance??? who pisssed in your corn flakes?

Of course the copper line may not be grounded but in 99% of homes/cases it is and it a simple DIY friendly method.

How about just adding to the conversation. I know LOTS of electrical but don't jump in to their forums/sites w/o showing some respect.:censored:
 

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Discussion Starter · #17 ·
drop your probes boys!
I also know some electrical but this home has been rewired by someone with NYC codes using BX cable and 12awg wire standard 15amp outlets. I will check that ground and i'll install a new ground rod and wire to the fuse box and to the HVAC unit.
Right now im waiting for the board so when it arrives, i'll recheck the wiring beore installing it and post my findings. Much thanks!!
 

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Yur Welcome:yes:

I suspect it is a grounding issue so improving it is a very good idea. apparently there is some condition in humid areas of the US and probably Canada where the screws in the air handlers corrode/loosen and they get a floating ground. some kinda galvanic reaction. have not seen it where I am but other Pro's I talk to have run into it and it drives them nuts troubleshooting. On some units I run a green ground wire from the ground of the board or transformer secondary/ground directly to the ground wire of the air handler for that reason. Bypasses any chance of loose board mounting or connections.

Let us know if the problem gets solved for others and future reference.:)
 

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Arrogance??? who pisssed in your corn flakes?

Of course the copper line may not be grounded but in 99% of homes/cases it is and it a simple DIY friendly method.

How about just adding to the conversation. I know LOTS of electrical but don't jump in to their forums/sites w/o showing some respect.:censored:
I apologize for my comment. Something hit me wrong and i shouldn't have snapped on you.

Again, I apologize.
 
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