Payne 90+ gas furnace model # 398 AAZ giving off burnt smell

[lnowack]

Yesterday night my gas furnace Payne 90+ model# 398AAZ approximate age 18-20years old started running very erracticly and giving off a burnt electical smell as if a motor or something burned out. I turned the furnace off since it was running like a car almost out of gas and the smell was too toxic. Any suggestions what might be wrong and what I can do?

Thanks,

Lars Nowack

[dkpd1581]

Check the exchanger tubes for rust and cracks that can cause erratic operation.  Visually check the motor windings and look for dark or burned copper and dark or burned strings that are used to tie the windings together.  Look for oil or grease along the shaft and motor housing - signs of bad bearings.  Look for scorch marks in the burner areas where the flame came back out of the burner area - signs of cracks in exchanger or obstructed flue.

First run it fan only and look listen smell.  If nothing after about 5 minutes of run time, engage the heating and again look listen smell to try and narrow down the occurrence to a motor failure or a combustion heating failure.

[lnowack]

Thanks for the advice, I checked all of your suggestions and it turns out it is the circuit board and the wire connector right above the board that burned, it started up when I ran the fan first. How much does a board like that cost plus the connector?

Thanks,

Lars