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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I am an HVAC tech working on a furnace where blower fan does

Customer Question

I am an HVAC tech working on a furnace where blower fan does not come on. appears to be two heat-sensing switches. Normal-looking (black back with two terminals going into hx) what i think is operational switch and another one (which i think is safety) by fan housing in blower cabinet. problem is that furnace will not fire unless both switches are closed circuit and then the fan never comes on (no power to fan at controller board). is board bad?
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

Can you attach pictures of switches in question?