Air Curtain

[gus6863]

I am an AC guy trying to help out a customer...
TX valve frosting up right after system is turned on. I was told the tx valve was replaced. I did not check superheat or sub cooling. The sight glass is clear. The temp in the box is high and it will freeze up the coil after running for a few days. blockage in valve?? It is freezeing from valve back to evaporator coil...moisture??

[jhd1234]

Go back to square one and get a full set of diagnostic numbers [refrigerant type, type of temperature control, evaporating temp, condensing temp, superheat, subcooling, ambient temp, box temp, TXV part number, compressor model number and so on]. Would you want your doctor to feel your pulse then diagnos cancer?

[gus6863]

I am going in tomorrow...I will get the info

[joemach]

I am an AC guy trying to help out a customer...
TX valve frosting up right after system is turned on. I was told the tx valve was replaced. I did not check superheat or sub cooling. The sight glass is clear. The temp in the box is high and it will freeze up the coil after running for a few days. blockage in valve?? It is freezeing from valve back to evaporator coil...moisture??

Clear sight glass or empty sight glass? No liquid to TXV?

[gus6863]

full site glass

[icemeister]

It would be helpful to have the model number of the case...or whatever it is...you're looking at. The term "Air Curtain" doesn't do much to describe it.

Is it an open case, glass door reach-in case, a walk-in box...?

Regardless of what it is however, you still need to determine if the TXV is doing what it's designed to do...control the superheat leaving the evaporator. Get the info you need to diagnose that first.

[gus6863]

ok I have more info;

Air screen made by Regal Pinnacle
M#SCAS48R Remote
S#06051774
R 404A
Condenser
Omni temp (Multi-unit)
M# WD4-AC-V-10-3
S#4930-D05
Copeland compressor
M#RS55C1E-CAV-201
S#04H19358D
uses a thermostat to close a solenoid valve and pump down
SC was 6 then up to 10 and back to 6
SH was 10 at condensing unit
13# suction
224# Discharge (taken at reciever)
Ambient temp around condenser was 80
box temp around 53
unit frost up at discharge of expansion valve as soon as it turns on. It freezes to coil and the external equalizing line freezes also.
Box was holding about 43 when I got there this am, but the coil had the back row frozzen. I defrosted it and these are the numbers

[icemeister]

ok I have more info;

Air screen made by Regal Pinnacle
M#SCAS48R Remote
S#06051774
R 404A
Condenser
Omni temp (Multi-unit)
M# WD4-AC-V-10-3
S#4930-D05
Copeland compressor
M#RS55C1E-CAV-201
S#04H19358D
uses a thermostat to close a solenoid valve and pump down
SC was 6 then up to 10 and back to 6
SH was 10 at condensing unit
13# suction
224# Discharge (taken at reciever)
Ambient temp around condenser was 80
box temp around 53
unit frost up at discharge of expansion valve as soon as it turns on. It freezes to coil and the external equalizing line freezes also.
Box was holding about 43 when I got there this am, but the coil had the back row frozzen. I defrosted it and these are the numbers

The expansion valve should never have frost on the external equalizer line. That valve is toast and needs to be replaced.

The low superheat you got at the compressor was mostly due to the flooding from the equalizer, not from the evaporator...which isn't doing anything because it's starved. This case should be running at about a 20 Deg F evap or around 55 psig.

Here the manual for this case:
http://50.22.131.158/~rpi/home/wp-co...II-Manual1.pdf