Walk in freezer 404a problem

[dangpgt97]

We all like a good mystery. You're gonna want to do a performance curve on that compressor. There may be some internal damage that's cutting the capacity.

[VTP99]

Seems the compressor valves may be not sealing right, the unit would pump down to a slight vacuum but not much, someone had the pressure cut out turned down as low as it would go, so on a pump down the system wouldn't cut off (no telling how long it had been like this). Its a recip. compressor.

I had that happen on a w/i cooler a few weeks back. Without my gages hooked up I felt the LLS and it was off. Yet the compressor kept running. My first guess was the valve was leaking. So I closed off the liquid line and still no off. Now I connect a low side gage and find it running at about 5 pds. suction. I disconnect the auto pressure switch on suction line and it shuts off. Replaced switch and all is well. Well I think this put some extra miles on that compressor because who knows how long it ran like that. And it will not go to vacuum. Yet the cooler still stays in the zone.

[skpkey9]

How deep of a vacuum is pulled is not a proper way to check a compressor if you truely want to know then as said earlier performance curve chart will help...Got a few compressors out there that will not pull a deep vacuum or not at all and have been running for years on ice machines and W/I's...

Glad you found the problem...

Hope this helps...

[marter]

can you give me details on doing this performance check ?

[jpsmith1cm]

Post model, serial, suction and discharge, volts and amps.

I'll walk you through it when I get home.

[VTP99]

can you give me details on doing this performance check ?

If your running a Copeland compressor go to there web site. Not sure with Tecumseh or other makes.

[jpsmith1cm]

Emerson/Copeland has a program that you can download.

Problem is they are stingy with the activation codes.

I did a thread a while back called "demystifying performance curves" on here using the Emerson program.

when I suspect a compressor has a valve problem, I run the numbers. It only takes a couple of minutes and it is good insurance.

[76olds]

Wow had no idea this post got so popular when i was at work
Dont you guys work too lol

anyway, got there this morning box at 14deg. pressures were same as yesterday, suction still reading too high. Had a completely clean coil.
Pulled gas out of unit, to eliminate the portability of mixed gases. Pulled a Vacuem and recharged.


unit acting the same, so pumped unit down, replaced TXV with a Sporlean, new LL dryer. Started it up, suction running around 20psi, box cooled down to 0deg.

Seems the compressor valves may be not sealing right, the unit would pump down to a slight vacuum but not much, someone had the pressure cut out turned down as low as it would go, so on a pump down the system wouldn't cut off (no telling how long it had been like this). Its a recip. compressor.

Question:

Original post you said you had a 50#suction. Was the original txv a z charge and the new txv a zp charge?

Just wondering if the compressor is getting hammered coming out of defrost with high suction pressure and going off on overload when you were not there.

[EugeneTheJeep]

Torch the receiver.

Could you please explain this procedure?

I had a box tripping the HP CO on warm days, I removed a bunch of refrigerant, the site is flashing, but it is working like this, an R22 Med temp WI cooler.

[kelvin]

Its got a alco style txv, this is what the other tech and I came up with a likely problem, the txv isn't feeding the coil right, and getting alot of liquid coming back up. Or there is a chance it could have some moisture in the system.

im not a full time refer guy

Suction pressure too high. Adjust the TXV. Should be around 10 - 15 psig.

You are right you are feeding to much liquid on the evaporator. The refrigerant is not evaporating. The efficiency of the system is less.

Seems the compressor valves may be not sealing right, the unit would pump down to a slight vacuum but not much, someone had the pressure cut out turned down as low as it would go, so on a pump down the system wouldn't cut off (no telling how long it had been like this). Its a recip. compressor.

Sounds like you slugged the compressor because your feeding liquid. Checked if your pulling vacuum. If not change the compressor or valve plate then adjust the TXV.

[fool4school]

Could you please explain this procedure?

I had a box tripping the HP CO on warm days, I removed a bunch of refrigerant, the site is flashing, but it is working like this, an R22 Med temp WI cooler.

Can you tell the liquied level by the frost line on the reciver???

[jpsmith1cm]

Could you please explain this procedure?

I had a box tripping the HP CO on warm days, I removed a bunch of refrigerant, the site is flashing, but it is working like this, an R22 Med temp WI cooler.

Let's take this Pro side.