Problems with Flowmaster Thermoswitch on Attic Fan

whitedavidp

Premium Member
Joined
Jun 23, 2012
Messages
15
Location
Seattle
Model Number
915379
Brand
-brand-
Age
1-5 years
Hello and thanks for any help you can offer...

Years ago we installed an attic fan and it came with a Master Flow 915379 thermostatic switch. Basically my problem is that this is just not accurate. Even when set to 85 degrees, this morning at 7am the fan was running. A digital thermometer in the attic showed 68 degrees. I note that sometimes just moving the setting on this switch the very slightest amount - sometimes just touching the knob with a screwdriver and not even turning - the fan's state will change.

I have never been impressed with these units and I think I have replaced one already. Do these just wear out? Are there reasonably priced alternatives? Maybe something digital and not just a bi-metal spring? Is there some other bi-metal spring based unit that is superior? This is just stupid.

Thanks
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,369
Location
Murray, Utah 84107, United States
They just wear out. You can pick one up at any of the home centers or Walmart for about $25. I don't know about a digital replacement. If you're looking to replace the entire system you might find something digital. Just do a google search.
 

whitedavidp

Premium Member
Joined
Jun 23, 2012
Messages
15
Location
Seattle
Thanks Rick. I guess you are correct. I am surprised they do wear out. But that seems the case. Cheers
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
34,369
Location
Murray, Utah 84107, United States
I really couldn't tell you. I don't recognise the brand but I don't get a lot of HVAC calls, at least not enough to be able to compare brands. Sorry
 
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