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crabzilla 07-07-2008 09:46 PM

Carrier AC Problems...Please Help!!!
Hi All,

I'm new to the forum, but a die-hard DIY'er. Here's my problem:

Friday night we had a thunderstorm in the area, didn't hear any thunder nearby, but did off in the distance. Woke up Saturday morning to flashing 12:00 on all the clocks. Didn't think much of it until I got home Sat. evening and the house was pretty warm. Checked the tstat and no go. Sunday, I opened the indoor unit and checked the control board, sure enough, the high side inputs were blown off (has happened a couple other times and a circuit control board change was all it took to repair). Bought replacement board today and installed it. Now the outdoor unit runs just fine, but no indoor fan. The condensor coils are getting nice and cold. Here's the basic diagnostic stuff:

1) Unit FKABNF002, circuit control board: CES0130007-00

1) 240 input on the yellow/black (on the 12 plug rectangular power jack) 120 on each side.

2) M1 and M2 (motor leads are yellow and black) 120 each 240 total

4) T1 and T3 are tapped to the transformer (120 each total of 240)

5) SEC1 (red) 25+ V and SEC2 (brown) 0 V

The straight 7 pin connector shows the correct voltages starting from pin1:

1 - 0
2 - 25+
3 - 0
4 - 0
5 - 25+
6 - 25+
7 - 6+ ???? (my book shows it should be 0)

My Mother is in town for the week visiting her grandkids and she will be getting very grumpy if I can't get the AC on in short order....PLEASE HELP!!!!

At this point I'm thinking maybe the surge from the storm knocked out either the transformer or the fan.



statman 07-08-2008 08:30 AM

Transformer looks okay from your readings. How about your fuse on the board? Make sure to check it. Also check your voltage to your fan motor when the unit is in cooling mode. There is a cooling speed tap on your board (generally a black or yellow wire is attached). See if that helps you narrow it down.

crabzilla 07-09-2008 10:45 AM

Hey Statman,

The 5amp automotive type fuse on the circuit board is good (and a spare tried as well). I think I've isolated the problem down to the ICM portion of the fan motor...I pulled the ICM out yesterday and a visual inspection of the PCB shows a blown electrical trace on the back of the PCB. The fan motor spins freely, so I think it's the ICM.

Going to pickup the part shortly and we'll know soon whether this is the problem or not.

Thanks for the help!

crabzilla 07-09-2008 03:25 PM

Problem solved. The thunderstorm we had must've sent a surge that blew both the Control Circuit Board and the ICM. After replacing both, the system is 100% working (and Mom is happy with the cool house).

I think my next project will be to install a whole house surge suppressor in the service panel to, hopefully, avoid this kind of crap (and expense) in the future.

Best wishes....


wire_twister 07-09-2008 09:19 PM

had the same thing happen to my carrier ac about a year ago. I live on the east side of no-where so it took a week to get the part, what a miserable week that was

jbfan 07-09-2008 10:57 PM


Originally Posted by wire_twister (Post 137667)
had the same thing happen to my carrier ac about a year ago. I live on the east side of no-where so it took a week to get the part, what a miserable week that was

But you live on the west side of Clarks Hill Lake!!!:jester:

crabzilla 07-10-2008 07:47 AM

Wire Twister;

I feel for you for's not bad enough to pay insane amounts for these replacement parts, but to have to wait for them on top of that is enough to drive a man crazy.

I'm real lucky to have a Carrier Regional Parts Center like 5 miles from the house...just have to have my HVAC buddy call them in for me.

Best wishes....


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