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I have a lennox G43UF-36B-070-08 furnace and the fan is

Customer Question
I have a lennox...

I have a lennox G43UF-36B-070-08 furnace and the fan is constantly running but it is not blowing any heat

Contractor's Assistant: Did you double-check the thermostat's settings? And what about the filters?

The thermostat is set to heat and I changed the filters 2 months ago

Contractor's Assistant: Do you plan on doing the work yourself?

As much as possible

Contractor's Assistant: Anything else we should know to help you best?

The fan has been running since 7 pm EST and the inside temp is 63 with the thermostat set at 73

Submitted: 9 months ago.Category: HVAC
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Answered in 13 minutes by:
12/6/2017
HVAC Technician: airheatman, HVAC Technician replied 9 months ago
airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 9,539
Experience: Furnace, A/C and heat pump specialist.
Verified

I will be happy to help.Let me grab a manual on the furnace.

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HVAC Technician: airheatman, HVAC Technician replied 9 months ago

Look on the furnace control board and tell me what the little red and green led lights are doing. (EXample red slow flash and green on solid)

If you do not have a peep window on blower door you will have to remove panels and hold door switch in to have power to furnace and see lights.

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Customer reply replied 9 months ago
At first they were blinking simultaneously. Then after a couple of minutes the red might shut off and just the green light was blinking
HVAC Technician: airheatman, HVAC Technician replied 9 months ago

OK the blinking simultaneously means Power on − Normal operation.

Then when red light shut off and just the green light was blinking this indicates the pressure prove switch is open .

Does the small vent "inducer motor" start and continue to run?

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Customer reply replied 9 months ago
I don’t believe so. Just the fan runs
HVAC Technician: airheatman, HVAC Technician replied 9 months ago

Lets make sure. If the small fan does not come on to pull a vacuum on the pressure switch the burners will never light

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Customer reply replied 9 months ago
Looking through the little window, the burner never comes on
HVAC Technician: airheatman, HVAC Technician replied 9 months ago

Firts thing that has to happen is little vent motor has to come on.If the small fan does not come on to pull a vacuum on the pressure switch the burners will never light

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