How do I wire a timer into a two speed switch?
 

Ok, so I installed a whole house fan in the attic this weekend.(One of the hottest days of the year, I know- thats just how I do things!). Now I need to wire it. It has a two speed motor and a wall toggle switch. Here is the wiring diagram for it:

http://home.comcast.net/~docsab/wiring.jpg


I also bought a 12 hour timer, which is a single pole single throw switch. How would I wire it into the above diagram to control both low and high speed?

What is it you want to do with the timer? Just turn the fan on/off, or turn it on/off and cycle between speeds. If the former is your desire, I would recommend putting the timer at the power source (right before power comes in to the unit).

Where L1 is shown in the junction box, install the SPST timer. As such, the timer will cycle the fan circuit off without regard for the position of the Hi/Lo switch. The only word of caution is that you should ensure the rating of the timer contacts is equal to or greater than those of the Hi/Lo switch, otherwise all of the electrical smoke will leak out of the timer and it won't work any more. :D

That's funny...

Thanks Kazoo! I always seem to buy those leaky outlets and switches.

Now, if my luck holds out, my next day off will again be a blistering 90 degree sunny day so I can climb back into the attic to run wire and lose some more weight:)