Oil issues

[Acrisoft]

Hi

I know that whenever the condenser unit is above the evaporator a oil separator is necessary
because the oil can easily go down from the compressor to the evaporator.

But I still have some doubts.

1- Why is mandatory to use a oil separator in systems which temperature is under 10 degrees Celsius.

2- Why is necessary to use oil separator in systems which tube length is higher than 3 meters, even if the condenser unit is not above the evaporator, and why is necessary to add 100ml of oil per each 10m length ?

Moises

[Emmett]

Well,
If you doubt the manufacturers recomendations go ahead and do what you want and let us know how that works out for you! A great deal of research and development goes into refrigeration products.

[Acrisoft]

Emmett
When I mean I have doubts, I mean I still have to understand the reasons. Not only to apply the procedures.
Any help will be welcome.

[Grizzly]

Just how do you explain that the oil can run down from the compressor to the evaporator.
The system flows in the opposite way.
Sorry but I am confused by your statement
Grizzly

[Acrisoft]

Hi

I reformulated the questions :


1-Why an oil separator is necessary whenever the condenser unit is above the evaporator ?

2- Why is it mandatory to use an oil separator in systems which temperature is under 10 degrees Celsius.

3- Why is necessary to use oil separator in systems which tube length is higher than 3 meters, even if the condenser unit is not above the evaporator, and why is necessary to add 100ml of oil per each 10m length ?

I read this information in a Elgin condenser unit.

Moises

[mbc]

1- oil is goes to system with or without oil separator.
2- we use oil separator to minimize oil running to system.( good oil separator is about %95)
3- in low temperature we have high viscose for oil plus low flow rate per square m2 and also low drop pressure in piping(we have big size pipe in suction) compare to high temp.
4- we add oil to system to cover lose oil in piping and Valium of that depends on our piping sizes and length and also a lot of factors in system as same as your designing .
5 - to return oil we should have right slop in piping system and also U trap after evaporator.
6 - position of compressor is important not condenser to decided do we need oil separator or not also in large
system (NH3 & R-22 or other R-....) we should use oil separator

[Emmett]

First understand that oil is mistable and will move with the refrigerant in the system, wherever the refrigerant flows so does the oil

1-Why an oil separator is necessary whenever the condenser unit is above the evaporator ?

When the condenser is above the evaporator it is difficult to get the oil to return from the evaporator to the compressor, so an oil seperator helps keep the oil at the condensor


2- Why is it mandatory to use an oil separator in systems which temperature is under 10 degrees Celsius.
When oil temperature drops sufficiently it becomes "sluggish" it thickens up, when this occurs it makes it difficult to get the oil to return to the compressor from the other piping and the evaporator, again the oil seperator aids in keeping the oil where we need it at the compressor

3- Why is necessary to use oil separator in systems which tube length is higher than 3 meters, even if the condenser unit is not above the evaporator, and why is necessary to add 100ml of oil per each 10m length ?
The longer the pipe run the more resistance the oil must overcome to retun to the compressor, there is always a certain amount of oil that is out in the system so the larger the system the more oil we must add in order to maintain satisfactory oil levels at the compressor, again the oil seperator assists us in keeping the oil where it is needed at the compressor.

[Acrisoft]

Thank you all. Your explanations about oil are being very good and complete. Much courses give only superficial explanation about oil. e.g.: "oil must be inside compressor and not the system".

So when much oil leaves the compressor it's bad only because compressor runs without oil, and never because the oil is inside condenser, expansion valve, evaporator. I mean, oil is not bad for other system parts ?

[Emmett]

Thank you all. Your explanations about oil are being very good and complete. Much courses give only superficial explanation about oil. e.g.: "oil must be inside compressor and not the system".

So when much oil leaves the compressor it's bad only because compressor runs without oil, and never because the oil is inside condenser, expansion valve, evaporator. I mean, oil is not bad for other system parts ?

No clean oil is not a problem for other system parts, unless ther is too much in the system and then it can compromise some of the systems effeciency.

[soleowner]

It is also possible to have an inverted oil trap if the compressor or remote condenser coil is above the evaporator. I've seen this install on Data Aire and Liebert systems.

Manufacturer's recommend having an oil trap every 15 feet of rise of pipe.

Oil migration is the issue.:cool: