ICP 15 Ton Keeps blowing fuses

[dagarair]

Hey guys long time troller, first time poster. I have a ICP 15 Ton Packaged Gas unit that keeps popping fuses. First I thought it was a compressor issue but it did it in heat mode too. I took one compressor off line by disconnecting low voltage to one contactor and it lasted a little longer (2 weeks or so) then popped. In straight heat it popped. I am assuming its something to do with a part that runs in both modes heat and cool? Could it be a blower motor relay or something? I disconnected the Tstat and it still popped. Fuse is correct 5A and I have swapped parts around since it has 2 of everything other than Main board. Could this be a main board issue? Short of starting to swap parts blindly I really dont know whats going on with it. This one got me good!

Model # PGS180H300AB

[dagarair]

Also checked all areas for proper voltage etc and they all check out. T stat is out of the loop so thats out. Compressors spark independantly and sometimes in unison for a bit (like 1 week) then fuse blows. As you can see this has been an issue for a couple months.

Just trying to go back and see what we have done to this thing while not having the log in front of me!

[VTP99]

Your going to have to follow the low side circuitry and find what is drawing higher then rated amps.

[Rane69]

if your blowing the fuse on the board i would be checking the control circuit maybe your tstat wires are chafed somewhere or wired incorrectly transformer,contactor coils blower relay etc

[Accurate Joe]

You need to isolate the problem. First instead of fuse attach small 3 amp breaker to alligator clips and use that. It saves fuses. Next cut off power and start ohming out the wires that are attached to the board. I have seen shorts in wires that went to devices on package units that wasnt even hooked up. (like wires going to economizer, but no ecomomizer.) Most of the time its a wire rubbing something and it has rubbed through the insulation. Look for that. If all else fails, try megaing out wires to find shorts. Good Luck

[Dallas Duster]

Check the wires in the evaporator section that are going to the 2 high limi`s for heat. The wires are usually tied to the indoor blower motor. I would bet it`s there.

[dagarair]

THanks! Going there tomorrow to have round 983745345 with this bastard. I'll let you all know what I find. :grin2:

[MUNC]

had a similar problem years ago with a rtu and low and behold it was in the fire alarm circuit. the RTU sent power down to the fire alarm panel thru norm closed contats and back to RTU. the wires some where below where chaffed. had alarm company pull new wires and no more popped fuses.

[missnu]

I had the same issue and as the poster above stated, check the fire circuit. That's where my problem was at.

[hvacprodmgr]

THanks! Going there tomorrow to have round 983745345 with this bastard. I'll let you all know what I find. :grin2:

So ..... What was the final result ??????:confused::confused::confused: