Anyway To Wire This?

Mike Finley

I have an exhaust fan I installed in my garage to suck the hot air out in the summer. It is hooked up to a thermostat so when it hits a certain temperature it turns on automatically. This thermostat is connected to a switch so I can turn it off if I want to.

Unfortunately the way it is set up I can't turn it on manually, it will only go on if it hits a certain temperature in the garage. Is there a simple way to also wire this so I could overide the thermostat and turn it on manually?

Right now it is wired with power going to the switch which is at ground level, and the switch wire runs to the thermostat which is up in the garage peak and connected to the exhaust fan.

mdshunk

So, you want the switch to turn it "ON" manually, but no longer want the ability to turn it "OFF" manually? Yes, you can wire this, but it will require a wiring change. The easiest way to explain this would be to draw you a picture. You'll notice that this will also require changing the cable between the switch and the fan location with 3 wire cable. I omitted the ground wire in the drawing for clairty, but naturally, you need that too. If you desire to turn the fan "on" and "off" from the wall switch, that's a different diagram. Repost if that's what you want to do. This diagram only overides the thermostat:

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Mike Finley

I knew somebody would know how to do this. So your diagram shows that with the switch open, they thermostat would always be powered and would turn the fan on according to the temperature set on it, and then if you close the switch, that would override the thermostat and turn the fan on?

So adding another switch before the switch in the diagram and the thermostat would allow me to turn it all off also?

mdshunk

Yes, and yes. You'd need to label this, though. I can see somebody (like me) scratching my head in a year or two trying to remember what switch was what there.

Mike Finley

Thanks for you help on this, next time I get a break I'll be rewiring it.