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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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The inthertherm furnace lights and runs normally but when

Customer Question

The inthertherm furnace lights and runs normally but when the main fan turns on it blows the flame out after 13 to 20 seconds.it is an electronic ignition ,The furnace is about 5 years old.
JA: Did you check the furnace's filters?
Customer: No
JA: Do you plan on doing the work yourself?
Customer: Yes I am a contractor. The door is off to the furnace
JA: Anything else we should know to help you best?
Customer: After trying multiple cycles twice the pressure switch code flashed but went away.You can see the flame be blowing around and getting smallerrors before it geasy blown out. The furnace will then restart and run again until the flame is blown out.
Submitted: 9 months ago.
Category: HVAC
Expert:  airheatman replied 9 months ago.

If blower is blowing flame around, you have a defective heat exchanger allowing household air to blend with combustion air.