So I have a RUUD Achiever Series compressor and air handler, electric heat and AC. The other night it go pretty cold so i switched from Cool to heat and it kicked on and kept the house nice. Nothing out of the ordinary occurred, burning dust smell for a couple minutes but nothing else, and in the morning i shut it off. Well the weather swung the other way so i turned it back to cool. Wouldn't you know it nothing happens. I checked the circuit breakers, all of them including the one on the air handler itself and nothing. Checked and replaced the air filter, and batteries in the thermostat. What i can tell you is the thermostat clicks twice but does not engage either the compressor or the air handler. In the past its always been the air handler that came on but the compressor wouldn't run, fixed that with a new switch, sometimes a capacitor, but this time i have no clue. Any help or leads before I have to call out to an expensive repair service, would be appreciated.
I would check that all the low voltage wires are tight in the thermostat and air handler. After that, use an electrical meter and see where the low voltage power is stopped. That will tell you where the problem is.