Walk In Cooler Advice

[uzzo2]

I have a customer that owns several convenience stores asked me to come by and look at one of his today. I don't have a lot of experience with them, so I thought I'd try here. I went the day before Thanksgiving and all indications to me were that it was low on freon. The pressures were low and the sight glass had a lot of bubbles. I added several pounds of freon, the sight glass never did clear up. He called me today and told me that the suction line and some of the compressor was freezing. I went back over there and he was right, there was some ice on the suction line and compressor. The weird thing is that it's cooling properly, everything in the cooler was between 35 and 38 degrees. Today I took the end plates off both evap coils to inspect the txv valves which is where I was leaning at first. But there was no ice on either one of the valves, everything in the box looked good. I turned the T-Stat way up to see how it was going to shut down. When the valve closed, the low side pulled down to around 6 psi before it shut off. I took the cover off the pressure switch and it was set at 25 psi, so I think that there must be a problem with the pressure switch. I don't think that's causing the problem that he's having though. What's strange is while I was looking at the pressure switch, the unit kicked back on. I turned around and looked at my gauges, the low side was at about 20 psi. So there's some pressure leaking back somewhere, I'm thinking that it may be leaking internally in the compressor. The high side won't get above 200 psi and the low side not above 50 psi. I am leaning towards a weak compressor, what do you guys think?

[Chris_Worthington]

Moved to Refer & Ice

[jpsmith1cm]

the sight glass never did clear up

Problem #1. Without a solid column of liquid to the TXV, you cannot make any real determinations about it.

there was some ice on the suction line and compressor

So what?


Let's say it this way.

Stop fooling with the controls and guessing about this or that without a proper system charge.

Get the charge right, set the superheat at the evaporators and re-evaluate.

[spinning wheel]

He said it perfect. You must charge unit first. Welcome to commercial equipment. It holds a lot more refrigerant that you are used to using. Once glass is full check superheats and your problem will go away. One of my pet pevs as well. We use refrigerant! FREON is a trade name. Not every car is a Chevy is it? Thanks and good luck.

[uzzo2]

He said it perfect. You must charge unit first. Welcome to commercial equipment. It holds a lot more refrigerant that you are used to using. Once glass is full check superheats and your problem will go away. One of my pet pevs as well. We use refrigerant! FREON is a trade name. Not every car is a Chevy is it? Thanks and good luck.

Thanks for the advice guys, I put over 10 pounds of refrigerant (thanks for setting me straight on that one) in it. I don't see how there's any way it could hold that much of the stuff bone dry. When I was there last Wednesday, the sight glass did finally clear up. But by the time I got all of my stuff on my truck, it had bubbles in it again. It actually looked like it did before I even started, almost like I never put an ounce in it. I'll go back over there and do what you guys say though, thanks again.

[markvilleman]

What R in the system?After the sight glass clear,what's the SH and SC?Did you mean bubble appeared in less than an hour after the glass clear?

[uzzo2]

What R in the system?After the sight glass clear,what's the SH and SC?

It's R-22, I haven't checked the SH & SC yet, that'll be on my list when I go back over there. I couldn't have checked anyway, the sight glass didn't stay clear long enough.

[pdrake65]

Most likely you have a leak in the system somewhere.

[markvilleman]

It's R-22, I haven't checked the SH & SC yet, that'll be on my list when I go back over there. I couldn't have checked anyway, the sight glass didn't stay clear long enough.

Did you check leak before you charge the system?

[jpsmith1cm]

Torch the receiver.

[pdrake65]

Torch the receiver.

Good advice. Are you thinking broken dip tube?

[jpsmith1cm]

Good advice. Are you thinking broken dip tube?

[chnrgr]

When you charge these systems you need to allow it to come down to temperature before you can rely on the sight glass. It sounds like you do have a leak in the system. The gas went somewhere.
Start with a visual looking for oily spots, then go the bubble route. At last resort push in some UV dye and come back in a week. That never fails