I would like to have the fan turn on and blow non-a/c. I only see 2 wires coming from the thermostat. Inenter image description here

  • How about providing the tech info on your thermostat? – JACK Jul 2 at 11:09

You have a simple setup with R (24V power) and W1 (HEAT). The fan is turned on automatically, along with HEAT, when the thermostat applies the power from R to the W1 connection.

The FAN terminal is labelled G and you need to connect that to the G terminal on your thermostat. Then, provided you have a FAN ONLY setting on your thermostat, it can control the fan independently.

You're going to have to run a "G" wire though since the currently line appears to only have 2 wires.

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    I agree lots of times I add a simple toggle switch on the furnace for this application. Between R/G terminals switch on turns on the fan if in a closet or attached garage it works fine even doorbell wire is enough for this or some automotive wiring like for trailer lights will be fine. + – Ed Beal Jul 2 at 20:02
  • Thanks for the answers! Just the answer I was looking for. I think I will just run a jumper between the R/G terminals. Strangely this furnace is in a green house I am using. – Paul Jul 3 at 13:17
  • I jumped the R/G terminals and the fan came on but it is going at low speed. Any way to make it run at full speed? – Paul Jul 3 at 14:41
  • You'll need to refer to the unit's manual. There doesn't appear to be a fan control on the board that you shared a photo of. It's possible that in fan only mode, the unit runs the fan at a lower speed. – jwh20 Jul 3 at 15:49

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