The A/C at my lake house stopped working and I had a bad repair call.
The tech decided that the circuit board was not working and physically
damaged it when he took it out. When I checked out the system I
determined that the circuit breaker was the real problem. Any idiot
with a volt/ohm meter could see the breaker was bad.
I got a new circuit board and installed it myself using the wiring
diagram - it was very straightforward, and I replaced the bad
breaker. When I turned the system on it worked fine, except I could
not turn it off at the thermostat.
After some investigation, I found that the thermostat had been
completely re-wired, the red on the green, the green on the red and
other problems. I suspect that was the result of a visitor to my lake
place desperately trying to get the system working.
After I rewired the thermostat, the system works properly in terms of
the low voltage controls sending out the right voltage on a specific
setting, for example the fan comes on when the thermostat is set to "
fan on". When you set the compressor to start by moving the control
level on the thermostat below the actual temperature, the 24 volt
control to the starter relay on the thermostat is activated - but the
relay does not close. I have replaced the relay, but that did not
solve the problem. I would expect that when the 24 volts gets to the
relay terminal, the relay should close, even if it is not hooked up to
the compressor, but that does not happen. I have the relay wired
properly. I have a Coleman Air handler and a Trane 2.5 ton compressor.
Any help would be appreciated.