I have a Lennox G40uh-48c-110-15. no LED lights. I replaced the ignition circuit board, and the thermostat. stil nothing. We recently had power brown outs and falures due to storms, the main circuit breaker
was fried. I get 120 on board, but no 24 volt on red / common terminals on board. I jumpered the blower and it works.
JA: Just to clarify, do you think this is a larger HVAC problem, or something specific to the thermostat?
Customer: I don't know.. it was working in the morning , then stopped all togehter...
JA: Do you plan on doing the work yourself?
Customer: I already have replaced the circuit board and thermostat. coul power issues throw the flameout sensors, or limit switch?
JA: Anything else we should know to help you best?
Customer: can't think of anything else.. but I am not getting 24 volts on the Red and Common terminals of the Thermo at the furnace so I am wondering if there is a way to jumper the thermo terminals at the furnace to rule out the new thermostat or the wires even.