Subcooler testing?

[jpsmith1cm]

It might seem pretty simple to test a subcooler, but leave it to me.

Was looking at one yesterday and trying to test or prove performance. Mostly for my own satisfaction, but also am looking to make this a part of annual testing.

Inlet liquid temp was 66 degrees.

Running full subcooling which was a 5 ton valve, I think, at a 40 degree evaporator temp. I measured 2-5 degrees superheat on the subcooler.

Outlet temp was 67 degrees?

Something doesn't add up here. What am I missing?

[Phase Loss]

these reading do not make sense

First checks are to make sure your subcooling circuit has a solid column of liquid feeding the TEV.

Then make sure your liquid to be subcooled is a solid column.

key point here being (you cannot subcool vapor)

Then your subcooling circuit should have around 10 to 12* superheat (40*SST with a 50* sensible suction pipe temperature)

Your liquid to be subcooled is entering at 66* and should be leaving towards the liquid header at around 50 to 55* sensible pipe temperature.


The readings you provide give me the impression that your subcoolers TEV is leaking through the push rods and into the externally equalized line. Giving you a low superheat reading, with no active heat transfer on your liquid to be subcooled.

[jpsmith1cm]

these reading do not make sense

First checks are to make sure your subcooling circuit has a solid column of liquid feeding the TEV.

Then make sure your liquid to be subcooled is a solid column.

key point here being (you cannot subcool vapor)

Then your subcooling circuit should have around 10 to 12* superheat (40*SST with a 50* sensible suction pipe temperature)

Your liquid to be subcooled is entering at 66* and should be leaving towards the liquid header at around 50 to 55* sensible pipe temperature.


The readings you provide give me the impression that your subcoolers TEV is leaking through the push rods and into the externally equalized line. Giving you a low superheat reading, with no active heat transfer on your liquid to be subcooled.

Didn't make any sense to me, either, that is why I brought it here.

Solid column of liquid for both.

Didn't think about that happening with the TXV.

[Phase Loss]

Seen it happen a few times.

If you change the TEV, consider Sporlans Y1155. it is designed for subcooler operation.

[jpsmith1cm]

I knew there was a subcooler TEV out there.

It is a wide range valve, right? That would require repiping to do away with the dual valve arrangement. Might not be a bad thing.

[Andy Schoen]

I knew there was a subcooler TEV out there.

Who else would make a specialized supermarket flow control valve.

[frigeguy]

Sounds like you need to set the valve. Why would you remove the duel valve set up? the Y series works well in this application.
http://www.parker.com/literature/Spo...10/10-10-4.pdf