3 position switch for attic fan

[Jim Elbrecht]

I just put an attic fan in and just wired it direct for now.

I want to put a 3 position switch on it. [off, on, automatic]

The fan has the adjustable thermostat that turns it on when the attic is hot-- but sometimes I might want to bypass that. [In winter it will be off; in summer after a few hot days, if it cools off at night I want it to run all night.]

I thought this would be an easy thing to pick up, but neither of the borg's I've visited have anything that looks workable. Before I wander down to our local electrical supply place, is there some reason this is a bad idea? [and is electric supply my next best bet-- or an appliance shop?]

Thanks, Jim

[RBM]

[Goedjn]

I'd be mildly surprised if a real electrical supply shop didn't have an appropriate switch, but if not, you can always use a combination of 2: A spdt switch that swaps between auto- and allways-on, and a regular spst on/off feeding power to that.

[Stormin Mormon]

Since a thermostat is essentially a single single switch... how about wire a "always on" switch in parallel with the thermostat?

[Duane Bozarth]

"On" and "Auto", no "Off"...

[Jim Elbrecht]

Thanks for the correct terminology . [I had to look up 'bat type' - I was thinking about the flying mammal, not the baseball tool. Now it makes sense.]

I had pictured a knob type switch-- but now that I have the terminology I'll give the electrical supply a try & see what they have.

Using a gang box & a 3-way is an interesting idea but space is tight & I'll do some searching for the SPDT switch before I go that route.

Thanks to all of you for the suggesti>The switch you want is a single pole- double throw, with center off

[Wayne Whitney]

Leviton 1281, around $50.

Wayne

[Jim Elbrecht]

Thanks-- Ouch!$ - I think I'll go with the bat type. That'll also give me room in a single box for a pilot light.

Jim

[RBM]

[trader4]

The question that comes to mind is why you would want to do this at all. The purpose of these fans is to provide extra ventilation when it's very hot. What's the purpose of burning electricity to keep it running all night after the attic has cooled off? You can just set the thermostat somewhere lower. The attic insulation handles the bulk of the heat issue and should have no problem once the attic is below

100 or so. At that point, it's more likely you;re spending more money running the fan than you save on cooling. Plus, these fans, especially if there is insufficient intake, can acually pull conditioned air out of the house through holes around electrical outlets, recessed lights, etc.

[Wayne Whitney]

Is it acceptable (NEC-wise) to use a bat type switch at 120 VAC? If so, how would one mount it in a standard electrical box?

BTW, I did find one online vendor that sold a toggle-type switch for $30:

Cheers, Wayne

[SQLit]

Yes as long as the switches horsepower rating is greater than the motor.

[George E. Cawthon]

You are making it too hard. Just put in a double box and use two regular switches. The first is power on/off. The second is automatic/manual. The cost is the box, two 39cent switches, and another piece of romex for the third wire you need. I did this long ago for my attic fan because I wanted more control. While you are screwing around with this and if the original fan was direct wired, you might want to rewire so that it is easily pluged in and unpluged. I did that also because I needed to remove the fan for repairs before I finally figured out that the solution was replacing the original crappy fiber washers (thrust) with nylon washers.

[RBM]

[Jim Elbrecht]

In my part of the world [upstate NY] it *usually* cools off enough at night that sucking ambient air into the house will replace the use of a window AC-- and closing up the windows in the AM will hold the coolness all day. Right now I'm just opening the attic door to make it a whole-house vent overnight, but I'll be putting a closeable vent between the upstairs and attic at some point.

We spend a lot more money heating-- and in the winter if the attic gets to 150 degrees on a couple days I'd like to leave the heat right there. So turning it right off for the winter makes sense.

Having the ability to make the adjustments in the hallway rather than going up to the attic to make them makes them all the more likely to happen.

If I were in the south with central air it probably wouldn't be worth the effort, but where I am the attic fan replaces AC most of the time. [Past week is an exception- it has stayed muggy around the clock so automatic would be the way to go this week.]

Jim