I have an old (not sure how old) Bard natural gas furnace.
Model # C80D36A
Serial # L900660603
Pilot light is lit but burners won't light.
Any suggestions?

Going to have to check any limits, and the thermostat, and for voltage to the gas valve. Never heard of Bard, so it could be a powerpile problem, who knows. Probably have to call in an onsite tech for this. Should be able to trouble shoot it in a matter of minutes.