Defrost Control Board - On Trane XE 1000


With all the snow here in the northeast, the likes of which I’ve never seen around here in my lifetime, it seems like I get one thing fixed with my heating system and something else goes wrong.

Anyhow, my outdoor unit was froze over for the second time in the past few days this morning with consistant freezing all around the units coils. I’ve found a lot of help on here with regards to testing the defrost control board, however, this one looks to be a little different than those for which I have found the advice on. Also, I notice the loose red wire. Should this wire have not been plugged into the “NORM” pin? I have 2 of the same heat pumps and the heat pump that works fine is wired the same way, that is, the red wire was not connected on it either. Can someone advise me on how best to test this particular type board? Do I jump across the “TST” pin and the “FRC DFT” pins?



The manual should be available on the Trane website or you can go to one of the hvac discussion boards. Logic does not always apply so you need the manual. It would appear that the wire needs to connect to the normal pin and to the defrost pin to force a defrost cycle. The test pin could be something else. Leaving the wire disconnected could be the same as “normal” but with a different time interval.

Thanks Bruce. I did manage to find a manual on-line for the Defrost Control Board. I’m going to try a few things from that manual tomorrow.