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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a day and night furnace that's started tripping the

Customer Question

I have a day and night furnace that's started tripping the circuit breaker. Right now it won't start. it's blinking 3 quick green lights, if i reset the circuit breaker it will start flashing quickly on/off and everything will go on.
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

If circuit breaker is tripping we either have a motor drawing high amps or a dead short.

Expert:  airheatman replied 1 year ago.

The 3 flashes indicates pressure switch is not closing.On call for heat does the small vent fan come on?

Customer: replied 1 year ago.
correction, it's NOT tripping the circuit breaker. Just unplugging and plugging it back in will fix the furnace for a while. where is the pressure switch?
Expert:  airheatman replied 1 year ago.

OK, that makes a difference. Now your furnace has 2 motors. A small inducer (vent motor) and the main circulating blower motor, On call for heat the small inducer motor must come on and suck a vacuum on the pressure switch which is attached by a small rubber hose. Our fist step is to verify if that small motor is coming on.

Expert:  airheatman replied 1 year ago.

Inducer will be where vent connects and look similar to this

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