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Thanks in advance for any suggestions…and sorry for the long post.
So, my upstairs AC furnace will cool down from anywhere between 10mins to 2 hours then stop (Freon is normal). The Thermostat still shows cooling indications. I shot all the wiring at the thermostat even swapped the thermostat out with downstairs as a test too, all normal, I shot the capacitor, transformer, and the power into and out of the motherboard too, all normal. Freon is also good along with the blower motor. So electrically the unit and thermostat appear normal.
I had a company come and check inside and out and all appeared normal too. He told me after it fails to shot wires and what to look for. Everything checked normal after the failure. Their only suggestion was replace either the motor or board.
After it shuts down, I have to wait about 20 mins to an hour before I can even get the blower fan to run or the AC to run then the same issue happens again.
The furnace will run completely normal for hours in end it’s only the AC portion that’s doing this.
Tonight I left the door on the unit off and the AC ran for 4 hours (since the door was open it was taking in the 90+ degree air in the closet but it never failed). Once I closed the door to allow just cooling air to get pushed through the unit, it failed in 10 mins. Blower motor was not hot to the touch, thermostat was sending a run signal.
The unit is 2 years old, the house 17 years old. Could it be possible that the outdoor unit is too powerful for the old guts in the house (furnace/ducts) and there is too much pressure being passed through so it shuts down. As mentioned earlier, when I ask for heat everything runs normal. Or, is it possible the control board is bad?
I’m pulling my hair out. Thanks and sorry for the long post.
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