My HVAC is 'Day and Night Forced Air" and my problem is the flame after it is ignited by the auto pilot will not stay, the auto system goes to its cycle of purgingand lightoff but the flame will not stay lit. I already ensure that the furnace doors are placed properly and I believe my thermostat is working properly becuase I could turn on and turn off the unit.
Please help me troubleshoot and please provide information where I could buy replacement parts for the faulty parts of" Day and Night" Forced Air HVAC.
Thank you

Do you know if your furnace has a pilot or a hot surface ignitor? If it has a hot surface ignitor your problem may be the flame sensor, this is a small wire looking thing that is sticking up into the flame of one of the burners. It is mounted on a ceramic post attached to the heater with one screw. Take this out of the furnace and use a fine sandpaper or steel wool to polish the part that looks like a wire. Re-install it and see if it works.