HVAC - No Compressor run
The Coleman Mach 3 13.5 BTU HVAC has worked perfectly from 2008 until now.
Troubleshooting my RV HVAC unit. The thermostat says COOLING ON. I have fan control from the thermostat, but no compressor run.
The compressor resistance values properly check out on the 3 terminals with none being shorted. Capacitors tested to their face values.
I have 110V power coming into the relay on the board but no power out. So the relay isn't turning on. Testing at the board on the GL (Fan) terminal to the B- terminal shows that the fan runs at B+ voltage. Less than 1-volt shows at the Y (compressor) terminal. That would tell me that the thermostat is not sending the signal to turn on the relay to run the compressor. So, then I jumped the GL terminal to the C terminal at the board thinking that that should restore the necessary message from the thermostat. Nothing. Just nothing, no change, no compressor.
So it looks like it might be a thermostat problem, but if I jumper B+ power to the thermostat terminal (C) at the board, it looks like a compressor problem. I have not yet tried to wire around the relay at the board and I'm not sure if I should do that. Not sure what the ramification of that might be.
Bad Thermostat? Bad Board? I'm lost or missing something. Suggestions?
Troubleshooting my RV HVAC unit. The thermostat says COOLING ON. I have fan control from the thermostat, but no compressor run.
The compressor resistance values properly check out on the 3 terminals with none being shorted. Capacitors tested to their face values.
I have 110V power coming into the relay on the board but no power out. So the relay isn't turning on. Testing at the board on the GL (Fan) terminal to the B- terminal shows that the fan runs at B+ voltage. Less than 1-volt shows at the Y (compressor) terminal. That would tell me that the thermostat is not sending the signal to turn on the relay to run the compressor. So, then I jumped the GL terminal to the C terminal at the board thinking that that should restore the necessary message from the thermostat. Nothing. Just nothing, no change, no compressor.
So it looks like it might be a thermostat problem, but if I jumper B+ power to the thermostat terminal (C) at the board, it looks like a compressor problem. I have not yet tried to wire around the relay at the board and I'm not sure if I should do that. Not sure what the ramification of that might be.
Bad Thermostat? Bad Board? I'm lost or missing something. Suggestions?
