I have an older Heil Model# NDGG100AF01 S.S.#H551-23415 Furnace. My main 24volt 40va primary transformer burned up. Could that have damaged the fan relay and the main gas valve. I replaced the transformer, wire for wire with the correct grainger purchased part, but I still can't get the main gas valve to open and fire up the burners. Thanks, Tom

The question is did the blower relay or gas valve short out and take out the transformer. If your handy with a volt meter we will need you to check resistance on the coils.

Both Coils were burnt up. What you're saying is that the main gas valve could have done the damage to both, correct?