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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Indication is that combustion air switch did not close. What

Customer Question

Indication is that combustion air switch did not close. What could be the cause?
Thank you
Submitted: 1 year ago.
Category: HVAC
Expert:  Tim H. replied 1 year ago.

Hi, I'm Tim and I'm an HVAC expert here to help answer your question(s). Please provide all the information I ask for since I'm not onsite. At the end of our dialog you will be asked to rate my service, but please wait until then and all your question(s) have been answered satisfactorily. Thanks for your business!

This could be a bad inducer motor, a plugged or blocked vent, or just a bad switch. Also, the hose could be blocked or kinked.

Customer: replied 1 year ago.
I do not find any kinked hoses. I am not sure what vent may be blocked. I don't find an inducer motor listed on the circuit drawing.
Customer: replied 1 year ago.
Are you there?
Expert:  Tim H. replied 1 year ago.

Sorry for the delay. We are experiencing some site issues today. The motor that exhaust your combustion products is what I'm talking about. The venting is the part that exhaust the combustion products to the roof. As I said, a kinked hose is just one possibility.

Expert:  Tim H. replied 1 year ago.

Do you have this motor (called a booster motor) in your unit?