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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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My heating system (a B80 furnace) is not lighting the burner

Customer Question

My heating system (a B80 furnace) is not lighting the burner when set in auto and heat is called for, it does come on and then stays on (it doesn't shut down). The flame sensor has been replaced after cleaning the old one had no effect (it performs exactly the same with the new flame sensor) and the igniter is functioning correctly.
Oddly however, in Emergency Heat mode, the burners ignite and the system heats and maintains temperature and shuts off properly once temp. is reached....not sure what the issue could be???
Submitted: 1 year ago.
Category: HVAC
Expert:  gotoman for ac replied 1 year ago.

In your question you said emergency heat mode. Is this dual fuel system with heat pump. Russ

Customer: replied 1 year ago.
I believe times the thermostat will indicate "auxiliary heat" the modes on the thermostat are:
Emergency Heat
Expert:  gotoman for ac replied 1 year ago.

Place a jumper between Emergency heat and W2/AUX. Retro furnace it will work. Now. Russ