Air Conditioner Buzzing

[poboy]

Turned on my A/C after being gone for a couple weeks. Ran great like always for a few hours, then started making an intermittent buzzing sound. After restarting a few times to see if it would quit making the noise, I finally isolated it to what appears to be a solenoid that operates a valve in the freon circuit. Does anyone know what this thing is? I think it allows freon to circulate when the compressor starts. Pressure on the low side starts at about 80, then builds to about 93, then you hear a whoosh, sound, pressure runs up to 120, then comes back down. Sometimes it cools, sometimes it doesn't , just cycles.

[colemj]

It looks like a reverse cycle solenoid that is used to provide heating instead of cooling.

Mark

[poboy]

Makes sense. It is an SX 16 Cruisaire unit that has reverse cycle heating. Anyone know how to test it and/or remove and replace it?

[Hudson Force]

Not as a cure, but for confirmation, usually a tap on the solenoid will free it's motion and stop the buzzing. I had this problem with a former AC unit and I had an AC technician remove thr reversing valve because I never used it for heat.