Furnace Makes "Thunking" Noise
My furnace has started to make a "thunking" noise AFTER it turns off (there is a long cycle, furnace stops, 30 seconds later a "thunk", then the fan goes on for a bit...then it all starts over with the next cycle). By the way this began after a technician came out and cleaned the furnace and did a "check-up" The owner of the company came out and said it was not the ductwork; but a "bad weld" in the heat exchanger. He did not take anything apart or off the unit.. said he could "hear it" in the unit. The furnace is approx. 25 years old and runs fine. He told me to get a CO alarm and to replace the furnace (sent me an estimate of course) Any ideas? Thanks, Jasmine
If you can take the panel off to expose the fan switch then turn on the fan without the burner. If it thunks, feel the duct work for a spot that may pop with the added air pressure. Also, the fan may be loose, or there may be a loose panel on the furnace. C.
Thanks so much "C" for the ideas about my thunking noise. I'll get someone to try that...by the way..I've told a few people about the "estimate" he gave me for a new furnace and they were outraged...said it should cost half the amount he quoted; but probably there's something "loose" in there...NOT the heat exchanger. I appreciate you taking the time to post.... jasmine
I hopr that the "thunk" is a minor problem. I appreciate your getting more opinions on this. Contractors are like doctors always get more opinions. Good Luck. C.