What is it?

[hvac01453]

Working the other day on a walkin freezer, R22, and I saw something strange on the compressor. a control of sorts, what its function is I'm not sure. This s on a Copeland Semi hermetic. From the King valve along with the liquid line is a 3/8" lline that goes thru a check valve I think, then it goes up an acros and through a sight glass then a right angled electri solenoid valve the the tube goes Ito the compressor above the oil sight glass by about a foot, into the compressor just under the head by about 2". The liquid line just goes to the building as it normally does, just mentioning it is a common connection on the King valve.
Now when the unit was running (ambient 73) I noted the short line between the Sov and the compressor was frosted. I just finished charging the unit and it was a hot pill down. Any ideas what it is?
Mike
:confused:

[Glenn Moore]

Hi
It sounds like a liquid injection valve for de superheating .This is to prevent too high discharge temperatures as R22 on LT systems can run with elevated discharge gas temperatures, causing overheating and oil carbonization

[NH3LVR]

Mr. Moore has it right as usual.
I have found the controls a bit picky to adjust, if they are like the ones have seen.
Be sure the Discharge Temp stays below 225 F. (107 C).
This can be a problem even in a medium temp unit if you have a long suction line.

Not that it matters, but a have a Dear Friend in Leominster and have been to your Fair City.

[hvac01453]

Yes, this is the birthplace of the Infamous Johnny Appleseed (John Chapman). I did finally see the info in a **** Wirtz book on commercial refrigeration, and you are correct. liquid injection because they were using R22 in a low temp application which is I think a bit nuts! The lineset is about 80 -100' long to boot............ This was Copeland thing I think. Its lasted 12 years so far so I cant knock it. It looks way to easy to screwup to try see if its working properly, with the sensor, a printed CB and a fixed orifice and SOV, I think the only thing I can check is to see if its keeping the discharge temperatures under 225F. Thanks for the comeback. I saw somethin similar on a two compressor can by York but it was a TXV and went into the accumulator and was med temp, but it was to control low load conditions...