Tran TWE031E-SF-1B Not running except for fan mode only

dbucciero

I have a Tran TWE031E-SF-1B the fan runs in fan on mode but will not run in heat or AC mode. I replaced the ICM but it did not resolve the issue. Can it be the motor control board or something else?

ratio

Did it just stop working, or did something change, like a new thermostat?

If you leave the fan in the on position does the system work, i.e. heat & cool properly?

the_donut

I’ve seen that issue with part of a relay being fried on a simpler system. Not familiar with that model though.