SandySprings

I have a Trane XE90 and noticed that the thermostat wasn't on. I have two units so I switched the thermostat with the downstairs one (that was working) and it didn't work either. I then checked the furnace control board and it was a slow flash (Normal No Call for Heat). I opened the unit door, which disengaged the switch. When pressed the door switch I could hear a quiet buzzing sound which leads me to believe that there is power to the board. I'm wording if power's going to the thermostat. Oh I also noticed my metal pan underneath my furnace was full of water...it looks like the condensate line had been pulled away...I reinserted it and pumped out the water. I'm wondering if this had anything to do with the causing the error code. Does anyone have advice?

SandySprings

I also check to see if 24 volts were coming through to the thermostat and it is. I also jumped R/W and the furnace came on just like normal...blower and all. Advice?

kok328

Where did you jumper R&W, at the furnace or at the thermostat?

SandySprings

at the thermostat.

paul52446m

sounds like your thermostat is burned out. does your stat require 24 volt going to it. is there a common to your stat. the water problem must have shorted out the stat. does the wires for the stat go down where they would have got wet or did water get around the electronic board?. If low voltage wires got wet you might have a bad spot in the wire coating.
I would run new wires or check them out close. Paul

SandySprings

I thought the thermostat was burned out too, but when I connected it to my downstairs unit, it worked just fine. Yes the stat requires 24 volts, I think. I'm not sure what you mean by "a common to your stat." I think there's a sensor that trips my power when there's a certain amount of water.

I'll try to put my R & W back into the correct slots and see if my thermostat starts back up since the furnace has been running for a while.

SandySprings

Wow. Whatever I did seemed to have worked. My stat is working and the furnace seems to work like normal. Thanks for you help paul52446m.