Aprilaire 760 with RP 425 manual humidistat

agavrilo

I just moved into a new home and there is an existing installation of Aprilaire 760 humidified with RP425 manual humidistat. The humidifier is wired to humidistat only and will turn on regardless of whether the furnace is on or off based on humidity only. I would like to wire the humidifier so it only turns on when the furnace is on. The blower only runs when the heat is on so it would be ok to wire it so the humidifier is on when the blower is on. Since the Aprilaire 760 has its own power supply I am not sure how to wire the circuit so it would be open when the blower was off. I have a Lennox furnace with 20J8001 board. Thank you very much for your help.

diyorpay

Some diagrams at this site:

http://www.alpinehomeair.com/viewcat...categoryID=213

agavrilo

Unfortunately they don't answer my question. Is there a way without a current sensing relay?

beenthere

Need a relay of one type or another. That is energized by the blower, or a W call.

agavrilo

Thank you all for your help.