Hi, I had a new AC/Heater installed in June - recently we finished connected the gas lines and tried to fire it up. While the AC works, and the diagnostic LED remain solid, when we switch to heat, I see it flash on/off at about 2 second intervals immediately.

The book indicates that it could mean we are locked out due to excessive ignition attempts (we don't hear any evidence of this) or the auxiliary limit is open (and it doesn't appear to be). We've tested it with a multimeter and even jumped it out.

I guess my first question is, do I have the right code? Does it make sense to try to replace the circuit board? Igniter?

Thanks guys

((I had a new AC/Heater installed in June))

I would call the people that installed your heater. They should have given you a warranty for at least one year. If you mess with it you might violate the factory warranty.

Sometimes you have to undo the gas line and purge the air out of the lines manually, the unit will only attempt to start itself three time before have to be reset

Just a quick follow up - apparently my existing programmable thermostat is either damaged in heat only mode, or incompatible. Replaced it with another and the heater fired right up.