Trying to further troubleshoot Carrier Central Air Unit - Not Cooling

Old 06-06-05, 09:03 PM
Absolute Cycles
Visiting Guest
Posts: n/a
Trying to further troubleshoot Carrier Central Air Unit - Not Cooling

I have been trying to figure out this nightmare for a long time now. I purchased my home about 2 years ago and the heating and cooling was marginal at best, and then one day stopped working. I found that the evaporator coils were corroded and leaking and so I had them replaced and the system charged with fresh freon with a red dye additive so that I could see if there were any other leaks. All was well for several months and then the system started acting up again. When we purchased the house I found a digital programmable thermostat in one of the closets and decided it was a good time to install it and see if the problem is just a bad thermostat. problem went away for a long while, but eventually re-surfaced. What was happening and is happening now is this: Thermostat kicks on and reads stage I cool or sometimes stage II cool. Indoor blower comes on and blows are, but the compressor or condensor fan do not come on. When I checked voltage at the the thermostat I had 26v at the Y lead when ac was called, but I did not have voltage at the contactor switch at the outdoor unit. If I depress the contractor the fan and compressor kick on and start creating a cool charge. The only thing I have found to "look" wrong is on a circuit board inside the blower cabinet. This board looks like it has a transformer hooked up to it and the blower fan amongst some other wires. I noticed on the circuit board that one of the the resistors looked like it had been getting hot and when looking at the back side of the board I notcied brown burn like spots where the thing is soldered to the board as well as one spot just above it. I don't know if my problem is with the board or if the board is being affected by another problem, but I have a jumper set up to the contactor outside to try and cool my house down some for my young child, I notice this little resistor on the indoor circuit board is quite warm to the touch. I do want some cool air in my house, but I do not want to burn up my compressor or my house in the process. The guy who serviced my unit has been out twice to look at it. each time the unit started up fine for him and he could not find any issues and he said the pressures were within spec, right where they were when he serviced the unit. I feel like I have wasted his time and want to try and find a physical problem. Sorry for the long story. Any help would be greatly appreciated.
Old 06-06-05, 10:03 PM
Absolute Cycles
Visiting Guest
Posts: n/a
The circuit board I am referring to is the Air Handler Fan Control Circuit Board if this helps anyone to help me.
Old 06-06-05, 10:17 PM
Jay11J's Avatar
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
The Y from the t-stat has nothing to do with the board at the furnace...Unless you have a new variable speed blower.

Y should meet at the board from the t-stat, and another wire from the outdoor unit meets on the screw..

some outdoor unit may have a switch (pressure) that may need to be reset.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: