Originally Posted by acproblem
I do not think so the black was used at all - it is heat only thermostat. I have put new thermostat. I also think 1 wire from transistor is missing...normally tranasistor should have 2 wires correct ?
If it is red and white going to stat, put red from transformer to post 2 on the zone head, put red from stat to the other post of the transformer, put white from stat on post one of the zone head.