I have a problem with my Rheem central A/C where sometimes the compressor doesn’t engage. I’m hoping that there’s someone well-versed with A/C’s who I’ve helped with their computer problems once upon a time.
Here’s what happens:
When the air turns on, either automatically by the thermostat, or when I get home and do it manually, the fan always turns on, but the compressor only turns on sometimes. I don’t even have to wait to feel if there’s cold air, because my A/C has this neat “feature” where I can easily hear the difference between a working or non-working compressor, since there has always been a faint “refrigerant gurgling” sound that has always happened when the compressor first kicks in, even when the whole system was installed new, approximately five trouble-free years ago.
However the A/C turns on, if the compressor engages, everything is fine and it will always stay on until the thermostat reaches the desired temp and turns off. But, if either I, or the thermostat, turn on the A/C, and the compressor decides for whatever reason not to engage, it will always remain off indefinitely. That means, under normal operation, when the thermostat is driving everything, it will eventually attempt to turn on the A/C, but when the compressor fails to engage, the fan will turn on and never turn itself off, since there is no cooling taking place.
At this point, I have to intervene, otherwise the fan will just stay on forever blowing room-temp air. All I have to do is turn it off, wait literally a few seconds, then turn it back on again. The fan always turns on, but whether or not the compressor engages at this point seems to be about 50/50 - sometimes it won’t turn on, and I have to just switch off/on again until my 50% luck kicks in and it works. When it does engage, all is temporarily well until it cycles off and tries to turn on again later, then the 50/50 odds kick in once again.
I originally suspected that it was just the thermostat getting wonky, and after changing its batteries, I tried a little amateur diagnosis using the “Safe-T-Switch” installed in the condensate drain pipe. If the A/C is “ON” but the compressor isn’t working, and I manually trigger the float on the “Safe-T-Switch” to turn it off then on, that will have exactly the same effect as using the thermostat controls to turn off the A/C and turn it back on. IOW, sometimes using the “Safe-T-Switch” to cycle it off/on will cause the compressor to finally kick in, and sometimes it won’t, just like with the thermostat.
So, in my non A/C-expert mind, this eliminates the thermostat as the point of failure, since the same intermittent behavior of the compressor is exhibited when the thermostat isn’t even used to cycle it off and on.
Any ideas, suggestions, observations? I can do pretty much anything that doesn’t require specialized tools/equipment. If it comes to that, I’ll buck-up and call a pro, but if it might be something simple I can check for and fix myself, I’d rather do that.
Thanks!
(PS: Here’s another thread with someone having a different A/C problem. Since I plan on shamelessly promoting my thread there, I thought I’d share the favor here. )