After reviewing the spec sheet for the unit i have found that the LX series has a variable speed blower that will allow the unit to operate under low ambient conditions. Is specifies the system can operate down to 20 degrees. Anything below this and the system will not operate. If you do not have the LX unit and do have the standard, the. The unit is not permitted for low ambient use.
Most central air conditioning systems do not work under low ambient operation and doing so can damage the system. Residential condensers will very rarely come with a crank case heater for the compressor as well as a low ambient control that can modulate the condenser fan speed to maintain proper operation of the system. This is however common practice on heat pumps and ductless units. Most will only allow operation down to 32 degrees. A low ambient kit is normally required to lower the minimum operating temperature of the system.
The issue on running an air conditioner in cold weather is that refrigerant will migrate underneath the oil in the compressor crank case. When the compressor is then energized the refrigerant will rapidly change state as it is agitated and absorbing heat. This will cause the oil to be forced out of the crank case and will cause the compressor to run dry on oil for a period of time until the crank case has refilled with oil in the system. This can cause the compressor to fail. A crank case heater is utilized to prevent this by keeping the compressor pre heated.
So in conclusion if your system is the LX model it will stop operating when the outdoor ambient is below 20 degrees. The fact that the system is advertised for low ambient operation means that it is ok to operate down to 20 degrees.
If it is the standard model then you may have damaged the system from running it in low ambient conditions.
Sounds like a blown compressor.
Bad contacters don't usually pop fuses. And if it was simply the fan not coming on, the compressor should trip its own over-heat, not your breakers (unless it's old and grumpy: same prognosis; dead compressor).
If I were to keep trying to fix at that unit, the first thing I would do is install a "fused" (circuit breaker) disconnect for the condenser outside and a convenience outlet (both are now required by code).
That's step one of installing another unit, so it's no big loss if that doesn't help the diagnostics.
Air Conditioner Not Cooling : Tripping Breaker And Blowing Fuses –YouTube
My suspicion is we've got a bad compressor. Let me go grab my multimeter and get this thing tested out. Again, I'm going to go ahead and discharge the capacitor and then pull all the leads off the compressor. Then I'm going to go ahead and leave the fan motor connected and test. If this doesn't blow the breaker then that means our compressor's bad and it's time for either a new compressor or as old as this unit is, it may just be time for a whole new unit.
... It is as I suspected; the compressor's got a short in it. We're going to need either a new compressor or a whole new condenser unit. If I wanted to, I can recycle the fan top, the fan motor, and fan blades. That's a little bit more advanced troubleshooting and proving that it's actually our compressor that is down. We can replace the compressor if it's a clean change out. On this one, I think it's probably just maybe time for a new unit.
I've replaced compressors on commercial units (whose construction is conducive to such); it's not a very common practice for split systems, because that's the same amount of work, and you'd still have old equipment throughout.
Best Answer
Should be fine if you replaced a factory part with a part of the same size and configuration.