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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Have a 395CAV048111AGJA 80% furnace that runs then shuts

Customer Question

Have a Bryant 395CAV048111AGJA 80% furnace that runs for 24hrs then shuts off. also noticed that when furnace fires off draft inducer stays running is that normal operation?heater, coil,and 30"plentum is 140 degrees and flue pipe is 215 degrees doesn't seem right to me what should i be looking for
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, the draft inducer should stay running 30 seconds before the burner comes on, and stay running as long as the burner is on.

Those temperatures you gave are normal whenever the burner is on.

Something is not right with the furnace staying ' on for 24 hours then shuts off' however. If the burner stayed on for 24 hours the furnace should be over heating the house severely.

If just the main blower stays on for 24 hours, it could be because you have the 'fan switch' on the thermostat set to 'fan ON' instead of 'Fan Auto'.

Let me know a lot more about that in great detail, remembering that there are two (2) fans in that furnace, the small inducer fan that runs whenever the burner is firing, and the much larger main blower.

We can go from there.

Customer: replied 1 year ago.
the heater cycles normal for 24hrs then nothing i pulled a wire off the manual reset limit on the draft inducer and burner shuts off and main blower runs also tried it with hi limit and same i just don't know why its shutting down after working normal for a day and temps on the heater,coil,and plentum never got like this I'm assuming it kicks off on hi limit oil it cools down and by shutting the switch off when it doesn't come back on at call for heat just resets what ever fault is happening then fires normal again for 24hrs was working fine all winter til just the other day
Expert:  Phil replied 1 year ago.


I will need a clear, close up, very well lit and focused photo of the wiring diagram glued to the inside of the blower compartment door in order to coach you effectively on this. Use the paper clip icon at the right end of the tool bar above to attach the photo.

I will mark the photo up with trouble shooting instructions.

If I miss you tonight, I will pick up your response in the morning.