Poor cooling condition, compressor problem?

[jayryu]

The details as follows.

Unit: Open type merchandizer.
comp. : Copraweld RRS4-0075-IAV
Current box temp: 52F
Low side: 26 psi, 77F
High side: 182 psi, 101F
Superheat:50.1 , subcooling: 29.6
Refrigerant: R-12?
Captube system
RLA: 5.8
Actual Compressor amperage: 2.63
Ambient : 77F
Box temp setpoint : 35F

Compressor is running all the time but, box temp doesn't move at all.
Compressor failure?

[keapog]

Hi jayryu !
It seems like discharged unit . Less refrigerant in evaporator , less gas produced , high suprheat , less ammpere current drawings and the most problem less cooling effect . Try to add some gas very slowly untill you reach 12-18 k superheat .

[jayryu]

Someday ago, Condenser coil was covered with dust completely, then cleaned thoroughly. Before that it worked very good, but after the cleaning the temperature doesn't go down under 52F.
Thanks to "keapog" for your reply. Unfortunately I can't recognise what gas inside. Maybe R12 brand.

[Magoo]

wild guess, the filter drier is partially restricted and starving coil of liquid.

[Glenn Moore]

Hi Jayryu
Make sure the capillary tube has not been moved during the condenser cleaning, ie make sure the capillary is not touching the compressor shell or discharge pipe as this will cause the liquid in the cap tube to vapourise causing a vapour block and cause poor liquid flow into the evaporator

[jayryu]

I am thinking about possible captube and filter drier restriction now. But in my measured valve, condenser TD is about 54(SCT 131F- air in 77). If there is high side restriction,condenserTD has to be low. but it is too high.
And when I checked filter drier with feeling by hand, it doesn't seem to be any temp change exist. It is warm.

Condensing unit is on top of the cooler and evaporator section is under the botton compartment. Captube is inside the evaporator section. Therefore condenser cleaning and captube has no physical relations.

[jayryu]

I mean measured value. Sorry.

[Magoo]

relationship between cleaning condenser has everything to do with problem now, high discharge pressure has higher potential energy to feed liquid and as well scorch oil in system creating / adding to partial blocking filter drier. Touching drier for temp change should be done with infra red thermometer, and that will indicate a seriously partial blockage.

[NH3LVR]

Gas unknown?
We love a challenge!
Block the airflow through the condenser and watch the head pressure rise.
If this makes the low side go up you have probably found the issue.
Is there a fan cycling control for the condenser?

[jayryu]

I don't know what gas in it. but I know the compressor is for R12, and measured temp & pressure on filter/drier after 30 minutes stopping and found the gas is R12 characteristic. I'll try as Magoo and NH3LVR recommended.

[jayryu]

I couldn't go back to job site myself because of sick. During that time the job has been transferred to another company. So I don't know the results. Sorry for that. I myself are very curious.

[jayryu]

compressor model: RRS4-0075-IAV is R12 brand. is it possible to use R22 in this compressor?

[Magoo]

No not compatible. Compression ratios and motor horse power. Plus R12 and R22 are banned globally , drop into the real world. It is called global warming, Canada and the US seem to think that they are beyond this minor problem of screwing up the planet.
BC Canada no snow over ski fields, California /Fresno no rain no snow, sink holes etc..,
grumpy magoo, we endure the ozone crap and get fried by standing in the sun. Skin cancer is a major problem here, cheers ta and thanks everyone/not.