Refrigeration 101

[Gary]

Hi Gary, it’s been a long time since we had lunch in Michigan at Bob Evans :-) Hope you have been well.

Hi Rich. A very long time. Nice to hear from you again.

We installed a Russell freezer system last week and I thought of you. They are saying Copeland now wants 30F superheat at the compressor MINIMUM. They don't seem to care about the superheat outlet at the coil. What happened to Copeland’s 12F standard?

As far back as I can remember, Copeland has called for a minimum of 20F superheat and a maximum of 30F superheat at the compressor inlet.

Being a compressor manufacturer, their primary concern is the superheat at the compressor inlet rather than the evaporator outlet. No surprise there.

I have yet to see a system that can obtain a 15F sub cooling, the most I have seen ever was 10 and the newer systems seem to be around 4f. Is this due to a design issue? I always test a system before leaving to make certain it can pump down under load and not be a problem. Over 10f sub cooling I have yet to see possible. ?????

Are you measuring subcooling on the liquid line near the receiver?... or on the drip leg between the condenser and the receiver?