[RobsGreen]

Well I'm answering my own question, in case anyone else wants to know here's how you do it.

Buy a 24volt digital thermostat that controls both heat and cool. (you want cool) Next you need to get a transformer that brings 120volts down to 24volts so you can wire up the thermostat. Its quite small in size. You also need to get a 24volt 10amp relay which will turn the fan on/off. 10amp is overkill but thats ok.

So with that you can control the temperature in your grow box automatically. Here's a drawing on how it's wired.




There it is, its a pretty simple circuit. The 120volts going into the relay doesn't go throw the relay until the thermostat switches it. When that happens 120volts flows throw the relay and comes out the other end where the fan is connected.

Well I hope this helps someone out there, if anyone needs more info let me know.

One other thing to note, I mentioned I put a dimmer switch inline, thats a no no on AC fans I found out unless the fan is a variable speed fan, not likely the case. Using a dimmer switch will shorten the life of your AC fan quite a bit.