Oil changeover from mineral oil to POE in compressor

[aygul]

Hello,

We have a reciprocating semi hermetic compressor with mineral oil and i want to change oil to POE because i want to use this compressor in a cooling unit running with R407C...

First of all i would like to learn how can i removed the mineral oil from the compressor and before add the POE lubricant i have to vacuum the compressor or not? If these lubricants are mixed each other a little, is there any problem in running the system?

I hope i explain my questions enough...


Best Regards

[david.findlay]

To change over to POE you need to:
1 Drain the mineral oil & fill the comp with POE.
2 Run the system with with the existing refrigerant using POE
3 After several hours of running test the oil with a suitable test kit that is available from most outlets or refrigerant suppliers.
4 Keep changing the oil until the test shows that the mineral oil content is down to the required amount (normally <1%).
5 Recover the existing refrigerant.
6 Change any driers & components not suitable for the new refrigerant I.E. Xvalve elements, gaskets, O rings & seals (most should be OK but its worth checking).
7 Pressure test with OFN.
8 Evacuate the system to a good vacuum. 4 mbar should suffice except in low ambients, but thats a whole other subject.
9 Recharge with the new refrigerant & recommission the plant.
Remember to adjust pressure switch settings to suit the new gas.
& clearly mark the plant to show what gas it is now running on.

PS where in Turkey are you working? I spent some time working in Istanbul.

[aygul]

Thanks for your answer Mr.Findlay,

I am working in Alarko , Ýstanbul... I don't know Do you know Alarko before, but we produced ahu, cooling units, fancoil and other products related with heating in our factory.

Could you please tell me i have any chance to understand the quantity of left mineral oil without runing the system?

Your answer wil be appreciated...

Regards

Aygul

[Andy]

Hi aygul,
If your are fitting a secondhand compressor that has run on mineral oil onto a system that has been running on poly oil, simply change the compressor oil. Run the system up as you would after fitting any compressor (including a pressure test and evacuation), then test the oil after running for a few hours, that will allow you to detemine when you need to change the oil and when to re-test the oil.
If the compressor is dry inside, and it should if you are considering fitting it to a refrigeration system, you do not need to vac it out before adding oil.
Poly oil will not react with mineral oil in the short term, but over a period of month, under extreme load conditions. If you test and change the oil during the inital commissioning stages and you have a clean system to start with, poly oil will not cause ant adverse affects to your system in the long term
Regards. Andy.

[Dan]

There is one consideration that nobody has mentioned yet. The POE oil is an effective solvent. If you have carbonization deposits anywhere in the system, they will be loosened and clog small orifices such as TEV valves, filter screens, Sentronic oil failure sensors, etc.

Be prepared to clean these within days of changing the oil even if you have put new filters in.

[mike hamel]

Dan is right-- POE oil is a great solvent. When we convert from R12 (mineral oil) to R134a (POE oil), we get a crud-burst that lasts for days.

We put felt socks in strainers, and open-inspect them every few days.

We also have to change dehydrator cartridges very frequently for several months. They get clogged up.

[Dan]

we get a crud-burst that lasts for days.

I love it! Can I use that phrase without copyright infringement?