Reach-in cooler trouble

[football0220]

OK guys i am working on a reach-in cooler that had the compressor changed out prior to me working on it.Customer told me it has not worked properly since compressor was changed. Its an R-12 compressor so i pulled a good vaccum and put r-414b in the system. Its a cap tube system and my head is around 190 to 195 with 20 psi suction. The box was at 85 degrees and dropped to about 65 then the compressor would go out on overload and was extremely hot, it comes on again a few minutes later and goes back out on overload after running for about 5 more minutes. I cant feel any return on my suction line it just feels like room temperature. The cap tube was never changed out. Any ideas on what the problem may be im getting stumped, a part of me wonders if the guy who put this compressor in put the wrong one in but i cant find a model and serial anywhere on this box.

[kevincompass]

What is ur superheat and subcooling ? What about box manufacturer There's got to be a model number some where on the box.

[Dad]

Without giving advice on just how to fix it...

Could the cap be shellacked and is what took out the other compressor? It could be a running restriction cap tube thus reducing your back side cooling to the compressor.

A question I would ask would be, is the outlet end of the drier pointed down to create a liquid seal on the cap tube?

[football0220]

I cant find a manufacter or model and serial, this box is over 30 years old. I didnt check my super heat and subcooling yet. Having been doing this for about three years now i have very rarely got to work on any cap tube systems so im not sure what super heat and subcooling numbers to look for. The drier was not pointing down, actually just slightly upward and the cap tube goes up from there and comes back down to the evaporator, what does having the drier slopping down do for a cap tube system, like i say i have not messed with to many of them.

[Dad]

If it were me... I wouldn't spend much time on the SH/SC. I would check my PT chart for HotShot as well as apply my previous post.

You will find cap tube systems very sensitive to flash gas metering thus using the dryer as a mini receiver will eliminate this phenomena.

Sorry I can't be more specific but this is an open forum and direct advice is not allowed. Although this may not be much help... get your post count up and apply for Pro Membership and visit the Pro Forums where we can be more direct in our discussion.

[Joe Harper]

Your head pressure is way too high. How did you charge the unit, and how does the condenser look?

[jim147]

What did you base your charge on?

That box looks like it might run a little warm.

jim