No heat but working AC
I'm working on an old Carrier gas furnace 58PAV055-GC (15 years old) with currently obsolete control board CES0110057-00 which could be replaced with ICM281. The system doesn't turn the heat on when thermostat is set to auto. I reset the thermostat and replaced the batteries to make sure I'm Ok on this end. When swithed from auto to on the fan starts working but still no heat. The AC side is working perfectly fine in auto mode. I tried to diagnose the control board using the "self test" and the sequence is as follow:
-the inducer turns on and runs
-the gas valve/relay turns on (I can smell gas)
-the fan turns on in high speed then low speed.
After this sequence it starts all over. In normal mode the unit will follow above sequence only once than it will turn off. From time to time the inducer will start but no igniter or fan.
I checked the the voltages all over the board. They seem to be fine including the 3A fuse. My guess is that the control board is faulty but not sure about the igniter. I would appreciate your comments and suggestions.