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I woud like to wire up my exhaust fan to come on automatically when either my AVR/PJ or my HVAC is on. I think I figured out how to do it, but I'd like a sanity check. Here's the relay I'd like to use. It seems perfect since the coil is rated 10-30 VAC or VDC so it will handle both the 12 V AVR trigger as well as the 24 V thermostat voltage.

If I use two of these, I think I can connect the coil of one to the AVR/PJ 12V trigger, and the coil of the other to my HVAC thermostat. Then connect the contacts in parallel to supply the fan. Something like this.

Here's the part I'm not too sure about. I think this is how I need to connect the relay to the thermostat.

Anyone know if this is correct? Am I overlooking something?

EDIT: I forgot to mention, I've found one site that mentions the thermostat controls the fan during cooling, but the heat pump will control the fan during a heat cycle. Is that true? If so, this may not work as I'd hoped.

EDIT2: My diagram is for the thermostat connection should be between the G and C terminals. Ill try to fix that later today.
Edited by J_P_A - 5/7/13 at 7:50am