Presently, this furnace relies on combustion air pulled from within a well insulated tight basement. Frequently, the gas burners fail to light despite a normal ignition sequence and a clean HSI. They may light on the 2nd or 3rd attempt, but if they do not, the furnace locks out as expected under those circumstances. Of interest perhaps is that the burners always light if I have the front panel off to observe the ignition sequence.
Could a limited supply of combustion air prevent the gas valve from opening when it should? Also, once they do light, could that same limited supply of combustion air cause the furnace to run rich? The flames have more orange than I would like to see.
If the answer to these questions is YES, it will be a fairly simple improvement to add a 2" PVC direct air intake from outside the home. I may do that anyway.
If I'm way off base on this, then I'll have to investigate further.