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chillin out
02-04-2006, 10:38 PM
Hi Guys,

I have an Arctic circle HT pack that seems to have diluted the oil into the liquid?!??!
Looking into the sight glass shows near pure green dye that is put in to help trace leaks, you only ever see the dye in the oil (without the special lamp), never in the liquid gas.

Is this possible?

If so what causes it?

Any help appreciated.

Chillin:) :)

US Iceman
03-04-2006, 01:25 AM
Hi Chillin,

Since you posted the thread name as oil diluted it sounds like you already suspect the problem.

I have not used any of these leak detection methods, so I am not very familiar with them. My first impression is the dye is mixed with the oil.

Oil and liquid refrigerant are soluble in vary degrees. It would then stand to reason the dye could mix with the oil.

One quick way to tell if the crankcase is full of liquid refrigerant: is the crankcase heater on? Or is the crankcase cold?

mccoolair@yahoo
03-04-2006, 03:24 AM
Hi Chillin,

Just checking your post. I have been trying to troubleshoot a 404a dairy case not cooling up to spec.
In the beginning, the oil in the glass was a dark yellow, and at the very top of the glass. Their was ice on the suction line all the way up to the compressor, but the case temp was only 46 degree- the system never cycled off. It was like this when I reached the job. Compressor was sweating, crankcase- cool to the touch. I think it has too much oil, and is overcharged, but then the crankcase heater may be off!? Has anyone seen this kind situation?

Johnny Rod
03-04-2006, 09:14 AM
Chillin, as Iceman says the dye is mainly dissolved in the oil, and as some oil is always knocking about, this carries the dye around. I've only looked at fluoroscent dyes but the Spectroline instructions say the for oil-free systems you need to add a little oil to carry the dye. I guess some oil has made it out of the compressor, picked up the dye, and then been returned. The dyes themselves are solids at room temp hence the need for something to carry them - boiling gas would just leave them behind.

McCool - dunno, I'm not an engineer. Frosted suction line just means it's below 32F, have you measured superheat and T/P to see if there is liquid coming back?

chillin out
03-04-2006, 09:09 PM
@mccoolair, Are you talking about supermarket dairy runs? Do the cases run on EEV`s? if so..one or more of the cases is allowing the valve to open too much.
In any case you have liquid flooding back and lifting the oil.

This is not the case with my pack though, I know the dye colours the oil, but I have never seen it colour the liquid.

Crankcase heaters are working ok and there is an oil sep with reservoir so there should be minimal oil going round the circuit, So why is my sight glass(for the liquid refrigerant) showing loads of oil?

Chillin:) :)

US Iceman
03-04-2006, 09:29 PM
Chillin,

Does the pack use defrost gas off of the receiver?

US Iceman
03-04-2006, 09:38 PM
Their was ice on the suction line all the way up to the compressor, but the case temp was only 46 degree- the system never cycled off.

Have you checked the evaporator to be sure it is not frozen over with ice? :confused:

chillin out
03-04-2006, 10:57 PM
Hi US Iceman,


Does the pack use defrost gas off of the receiver?

No, all cases are off-cycle defrost.

Chillin:) :)

US Iceman
03-04-2006, 11:30 PM
Hey Chillin,

The reason I asked that is due to one system I have seen.

The receiver was setup for cool-gas defrost off of the top of the receiver. After many regular defrosts, the oil level in the compressor continued to decrease. Added some oil and all was well.

This went on for some time... Oil level decreased, add some oil.

During a shutdown of the system, I asked the chief engineer if I could remove the receiver and check for oil. He looked at me like I was crazy (maybe, but not this time :D ).

When the receiver was pulled off and drained, there was about 15 gallons of oil in the receiver. Enough to cover the dip-tube in the receiver and push it through the system. Hence, oil in the liquid sight glass.

This was a system used for research and development on a new product, but the same could happen in any other system also.

The regular defrost cycles allowed the oil to distill in the receiver.

If you have oil in the sight glass as bad as you seem to indicate, it may be something similar.

chillin out
04-04-2006, 12:15 AM
When the receiver was pulled off and drained, there was about 15 gallons of oil in the receiver. Enough to cover the dip-tube in the receiver and push it through the system. Hence, oil in the liquid sight glass.
This is also what I was thinking, but found no reason for the oil to go in there in the 1st place, unless oil seporator is goosed, which I have already given a size 10 boot with no results other than a sore big toe.

Chillin:) :)

US Iceman
04-04-2006, 12:46 AM
Is the green oil flowing through the sight glass or is the inside of the site glass just green?

Johnny Rod
04-04-2006, 09:30 AM
Thought you were talking about the crankcase sight glass, durrrr. Now I see.

dogma
04-04-2006, 11:44 AM
I'm only a green horn here but where I work we use
UV134a, and at a great additional expence.

We have green dye running all through our systems.

sight glass is always "green".

And yes it is missible with both the refrigerant and the oil.


??????????????????????

Maybe I have no idea what you guys are on about?

:) :)

willie
05-04-2006, 10:50 AM
if you have a sweating compressor and liquid in sump start checking your tx valve super heats sounds like your valves are open too much or over sized

chillin out
05-04-2006, 08:37 PM
Liquid line sight glass is clean, its just green due to the oil/gas flowing.

I have also been informed that the pack in question has had oil put in it several times, and no, there is no leak.

Every other pack does not do this, the liquid is clear.

Chillin:) :)