I have a fireplace which is setup with two thermostats and blower motor which is totally independent of my Carrier 58MXA Furnace. The fireplace works great and knocked off $1,000.00 from last winters heating bill. The fireplace blower dumps the heat into the furnance plenum thus is where my question arises. I want to ultimately wire another relay into this system to turn on the Carrier Furnace Blower when the fireplace blower turns on and dumps the hot air into the plenum. I have everything done except the wiring on the Carrier Furnace.
To set this up temporarily, before the relay comes in, I want to wire a on/off switch to the terminals on the furnance to just turn on the furnace blower when I want to add blower boost the the hot air thats being dumped into the plenum from the fireplace.
To start I should say that the thermostat has the fan auto/on switch which works as it should when I switch that to "on" position it just turns on the furnance fan blower.
I went to the manual and furnace today and jumpered the Green to the Red which I thought would just turn on the fan blower, which it did, but it also energized the A/C compressor. I then jumpered the Yellow to Red and it did the same thing by turning on the blower and energized the A/C compressor. I then jumpered the Green to Yellow and it did the exact same thing.
Can anyone solve this dilema of trying to just turn on the Blower from the terminal board on my Carrier 58MXA? What puzzles me is the Honeywell RTH230B thermostat when switching to Fan "ON" just runs the blower and does not turn on the A/C compressor.