Almost fooled!

[duke of earl]

Went on a service call this morning to check out a small refer unit that was installed to cool a concrete lab.Found HP switch tripped. Reset switch and checked Suction 70PSIG,
superheat at evaporator 30 degrees, Discharge 250 psig, subcooling 20 degrees, OAT 85 degrees, EAT 75 degrees. The lab is to stay humid for concrete testing I was told after scratching my head a while. I was expecting 8-10 degrees of superheat without really thinking about this process. I learned that we were only doing sensible heat removal, thus explaining the high superheat. I'm glad the txv was non-adjustable so I wouldn't screw it up. Just reminded to ask questions before making assumptions. An explanation of operation laminated and mounted on the side of the unit would be perfect for future service calls cause I can see the next guy going through the same confusion I went through.

[ej45]

Can you explain more.

[Edited by ej45 on 07-06-2006 at 10:10 AM]

[r404a]

Duke,

Whats up? Hope that all is well with you. Wondering if you have an MOP vallve there or if it was something in the way that it is sized. Later.


r404a

[duke of earl]

ej45,

What other info are you looking for?

r404a,

I just came off duty and it was a busy week/weekend.No MOP valve, just an epr. The system components were selected for a high sensible ratio.The condensate is actually being put back into the air to keep the humidity high.

[ej45]

Just curious about the concrete lab. What is the process for?

[duke of earl]

ej45,

I think they test concrete samples (unsure of the actual test) but humidity must be high to keep concrete from drying out.The concrete has already hardened so I believe it is stress testing.