My a/c went out today. Tempstar PGF024K060A. The inside fan would not work and the condensor fan was running. Turned it off and now all that it does is hum. I removed the cover and found the fan control board has burned up. The area that melted is on the bottom of the board and really only damaged the insulation on the 2 wires going to the compressor and outside motor. The outside motor was running before I turned it off. So I don't think it killed the unit. The unit is 8 years old. Could it have been overheated? Usually when you have a motor going bad it will overheat the wire causing the insulation to distort at the motor or away from the control unit. Is this a common issue? What do you suggest to do? Is there a common repair that you replace the board and also replace something else? Thanks for all that respond.

 

And be more specific as to what is humming? indoor unit or outdoor unit - what is burned? Tstat wire? or Main wire? What is not running, and what is running?

Do you have a volt ohmmeter and know how to use it? - If you dont...nobody here can help you. You cant DIY if you cant troubleshoot using our advice step by step. Furthermore, it sounds like a direct control voltage short - you must have some kind of electrical experience for us to help you find it. If you replace the board and there still is a direct short -it will burn the new board up (if its not fused) - providing the transformer is still good.

If this is the case, and I am correct, let me save you some money - thats why you came right? - Call a tech! It will save you from damaging the unit more or damaging yourself - or both! If I am incorrect, please forgive me and continue with your outline of the problems.

 

Yes, I have a fluke 78 and a 88 and peak voltage adapter. One for home and one for job. I am auto tech. The board itself is humming. This is a outdoor gas heat-a/c unit. The indor fan motor was not running but the outdoor fan was running. I turned the unit of then back on and now it only hums. I have a picture of the board if that would help. To me it looks like the board melt and damaged the wires. The wires that got damaged are the line in wires to the board. They are unused terminals that are damaged from the heat and the wire is only damaged a few inches from the board. I usually see the insulation damaged in muliple areas when it is a direct short. When I installed the breaker I saw arcing from the board to the hvac housing directly behind the board. And the fuses in the breaker box still did not blow.

I tesed the motors for a short and this is what I found. Red to yellow 40.5 ohms, yellow to black 32.5 ohms, and black to red 8.2 ohms. I applied power to the yellow (common) and black (cooling) and the fan ran. The condensor fan reads black to brown is 129.1 ohms, brown to red 166 ohms, and black to red is 37.0 ohms. removed the power supply lines from the circuit board due to arcing and pressed the jumper on the compressor/condensor switch (contact assy) The condensor fan and compressor came on and the evap got cold. Do you have the specs on what ohms the motors should read? I have the wiring diagrams and see how it is wired. How can I test the transformer?

 

Motor: Sounds like it works. From both the ohms readings -and - didn't you say you jumpered it and it ran? Must be good.

Transformer: 24 volts across the 2 outgoing wires of the transformer. 120 volts in, 24 out.

That board sounds suspect with that arc jumping and all, even though you only see burn where it should not matter. Probably something on it, like some diode or some relay that you can't see inside of that got toasted, be my guess. Or? - Any 3 amp fuse on the board?

 

Parts are suppose to be here tomorrow morning. I am going to replace the board and transformer. I found a place that sold me the transformer $7.10, board $73, and overnight shipping $26.50. I called numerous places in chattanooga and no one would sell to me cause I was not a dealer. Doesn't matter they were going to charge me $210 for the SAME brands and part numbers!!!! Thanks for all the information. The board has a hole on it about 2X2 inches.

Has NOT been My week!! Monday my dog got sick and had to take to the vet, Wednesday lightning storm got my satalite, Friday my dishwasher door broke, Saturday my a/c went out!!!