I need to know how to change out my transformer.
My thermostate is not getting voltage.
I still have the thermostate wires connected to the transformer but the hot wires are not. The fan is connected directly to the hot by passing the cool off my house

I need to know how to change out my transformer.
My thermostate is not getting voltage.
I still have the thermostate wires connected to the transformer but the hot wires are not. The fan is connected directly to the hot by passing the cool off my house

What kind of furnace do you have? Gas or electric? I would jumper the red and green, or the red and yellow, or the red and white at the tstat first, this bypasses the tstat to rule out the tstat being bad, did you check the breakers? Did you check for a fuse in the circuit board? Unless someone has caused a spark or shorted the transformer,, they don`t go bad very often

To replace transformer ,kill power at breaker remove transformer and replace exactly like the old one came off