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gotoman for ac
gotoman for ac, HVAC Technician
Category: HVAC
Satisfied Customers: 5178
Experience:  51 years of experience install design and repair of all makes and models of AC
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Blank thermostat, 27.8 volt at thermostat contact between R

Customer Question

blank thermostat, 27.8 volt at thermostat contact between R and (Y,W,G)
Submitted: 2 years ago.
Category: HVAC
Expert:  gotoman for ac replied 2 years ago.

If you have C terminal check between R and C on terminals. If not you have dead batteries or dead thermostat. Russ

Customer: replied 2 years ago.
I have 27.8 volt on the thermostat lead going from R to (Y,W, and G), there is no C on the thermostat. However, on the circuit board there is a C, when i connect R to C on circuit board the reading is 27.8.
This AM I was able to switch the thermostat to fan and heard the fan coming on, but the screen on the thermostat is still blank. I check the transformer and it looks fine. On the transformer it said that the secondary power should be 24 VAC. Should I be getting 24 volt to the thermostat instead of 27.8 volt?
I bought a new thermostat and installed it yesterday, so I know it cannot be the thermostat problem that you answer above.
Expert:  gotoman for ac replied 2 years ago.

Is this battery operated thermostat and what is model number of thermostat. Russ