[highdesert]

I've installed a Heil 90+ percent furnace and when the blower motor cutoff switch is actuated I hear a low humming sound. Is this normal? I should add this is not a cycle startup problem. It simply hums when it is off.

 

[yuri]

What is a blower motor cutoff switch? Switch to isolate the low speed? You may be hearing the 110/24 volt transformer humming and that is not a problem. If the customer objects then get a new one from ICP under warranty.

 

[highdesert]

Thank you, Yuri. The switch I'm describing is the safety limit switch that inactivates the blower fan when the front cover is removed. I suppose this switch powers the 110/24V transformer?

 

[beenthere]

Blower access panel safety switch.

Your hearing the low voltage transformer.

 

[highdesert]

Beenthere - Thanks - Chip