AC Condensor Vibration like earthquake, but only intermittently

Steve Garson_2

I have a Rheem air conditioner that has an intermittent problem that prevents diagnosis. On occasion, there is a vibration that literally shakes the house! The problem is that it never does this when anyone is near the condensor to witness it. The condensor is five years old and under warranty, but the service techs have never heard of this kind of issue. They tested everything and waited 90 minutes to observe the issue, but of course, it never happened. Only happens maybe once every few days for ten to thirty seconds. When it happens at night, it wakes the neighbor. Resistence and amperage on the compressor measures normal.

Does anyone have any ideas?

EBEBRATT-Ed

There are only two motors the condenser fan and the compressor. Are you sure the vibration is from the condensing unit?. Does the indoor blower run ok?

heathead

I wonder if the condenser motor is not turning some times and then it causes pressures to go crazy and unit to overheat. Don't know how to data log that. If it does it ie earthquake noise then run outside and see if fan is spinning.

Steve Garson_2

The challenge is that the vibration doesn't last long enough to run outside to observe. Very frustrating. The system cools just fine, it's the intermittent vibration that is the issue I am trying to solve. Might be that I just need to wait for a failure.

EdTheHeaterMan

That is why God invented security cameras. Point one at the outdoor unit. You may find that a critter is sleeping on the fan and it takes him 30 seconds to wake up and get off the fan. (just kidding about the critter)

mattmia2

Might check the current and voltage on both caps and see if they calculate something close to the values of the caps, maybe one or the other is failing and the corresponding motor isn't starting right sometimes.

EdTheHeaterMan

Sounds like slugging on a scroll compressor. Is there a crankcase heater on that compressor? Is it working?