Trane thermostat no power - http://www.hvacmechanic.com/ Forums

Original message

walker45

66.210.101.146

"Trane thermostat no power" , posted Mon 20 Oct 11:29

I have a Trane heat pump with gas backup yesterday I was checking the Gas furnace to make sure it started Ok I switched it to Emergency heat and turned it up 2 degrees and the Thermostat went blank and never turned on again The furnace had power the LED lights were working on furnace. What should I do to test tstat, the unit is only 3 years old, waiting to hear back from service. Didn't know if there was a fuse to check or where to check for voltage going to tstat or could it be a board on furnace.

Thanks

Replies:

RobertR

69.130.78.18

"Re(1):Trane thermostat no power" , posted Fri 24 Oct 23:48

Retired Mechanical Design Engineer that worked as an HVAC/R mechanic to pay for his education.

RobertR

69.130.78.18

"Re(1):Trane thermostat no power" , posted Wed 22 Oct 16:22

Retired Mechanical Design Engineer that worked as an HVAC/R mechanic to pay for his education.

RobertR

69.130.78.18

"Re(1):Trane thermostat no power" , posted Mon 20 Oct 18:14:

You have lost control voltage (24v a/c). The most likely candidates are usually all next to each other inside the indoor unit (AHU)on Trane. You have:
1. a blown control fuse (look for a black plastic holder near the control transformer with two wires going to it or they sometimes mount the fuse holder right on the transformer. OR

2. a popped control voltage circuit breaker (look for a round black plastic piece approximately 3/4" in diameter with a red or white push-button ticking out of it and press the button in the center one time only - if it does not reset you need a technician. AND/OR

3. you have a bad control transformer - for this you should have a technician check why the transformer failed.

Retired Mechanical Design Engineer that worked as an HVAC/R mechanic to pay for his education.

[this message was edited by RobertR on Mon 20 Oct 18:29]