It was hot in our house yesterday with all the cooking so I switched our system over to A/C. Everything worked fine. After it cooled down last night I switched back to heat and went to bed. When I got up this morning the thermostat was set to 70/Heat and the room temperature was 67. I switched back to A/C and set temp. to 60. Nothing happened. I can hear a couple of clicks on the thermostat but that's all. I set the fan to ON but nothing happens.

The PC board shows a red LED blinking continuously about once every second. If I'm reading this code correctly it means normal call for heat.

Any suggestions would be much appreciated.

Trane Model 4TCC043BCHCCA

 

Not sure if it matters but yellow and green LED's are not lit.

 

Do you have any condensate overflow safety switches? A meter would also show if you were getting a call for operation at the unit from the thermostat.
In the code schematic what does it state for a flashing red light?

 

Both slow and fast flashing red = Normal call for heat.

Where would I find a condensate overflow safety switch?

I swapped out a working thermostat with same results.

Thanks for the reply.

 

Do you have a meter and know how to use it?

 

Yes & yes but not needed.
In my original post I mentioned running A/C yesterday. You mentioned condensate overflow. I checked the pump reservoir and it was full. The pump plug has come part way out of the socket. Plugged the pump in, reservoir emptied and furnace came on. A nice, toasty 70 degrees now. SWEET.

Thanks so much for the help. You're the bomb and nice call.
Hope you have a great weekend.

 

Four gold stars for roughneck!

****!