Hvac company replaced my thermostat in the house with a new one when I got a new A/c. I want to use the old one in the shop. Just got a 125k btu Big Maxx. The thermostat works but will only run off the batteries. I have a G,RH,RC,W,Y terminals with a jumper between RH and RC. I am hooked to the heater on RH and W and the fan to G if I recall right. Works ok but always runs off the batteries. What do I need to do ? Got a simple thermostat to run it on for now. As a second note , not real happy with the heater yet. Seems like most of the heat is going out the vent.
Shop thermostat
- Thread starter MF294-4
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Jim greengo
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What do you have for choices on furnace end of wiring?
biggziff
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tom-ky
Well-known member
That unit should just use a 2 wire thermostat. I don't believe is has a transformer in it for 24 volts to work a thermostat like your house unit.
Jim greengo
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Picture of wiring on furnace?
biggziff
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The image I posted is the schematic from the manual for that heater.
Jim greengo
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Oops missed that,hard to see stuff on my phone.
According to that you should just need the R and W terminals from what I see.
biggziff
Well-known member
He's looking for 24V power to the Tstat. Neither of those wires will provide that.
Jim greengo
Well-known member
Cant see left side of diagram in his picture,but it does show the stat being fed from those 2 wires in the part of picture I can see.