O ring shrinkage and leaks

Hi all,
Leaks due to O ring failures have been discussed a few times over the years on the Industrial Forum regarding Ammonia but not so much with R22. One of our clients as a few large R22 systems still in operation and R22 leaks are unacceptable. These systems are old (40 years) and were made when R22 was "cheap as chips" which certainly is not the case today. This client has a contract with Mobil and supplies its own oil. Neoprene is recommended with R22 and is readily available from a local supplier. But Neoprene dose not last when in contact with Mobil 226E oil, over time the neoprene shrinks and hardens causing no end of problems. Even the Parker O ring bible is not much help.
Hopefully someone on the Forum can provide an O ring solution. Perhaps Kalrez although poor availability. Going OEM is a challenge on 40 year old valves but probably best. From what I understand OEM O rings are not your standard "off the shelf" O rings.
Thanks

Superfridge,
Can you advise what the "0" rings are on exactly, like compressor shaft seals, or valve glands?

O rings are all static seals on solenoid valves, sight glasses and stop valves.

Does Mobil have any input on the subject ?

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I might be wrong but Mobil 226E oil, is Gargoyle Oil. A synthetic oil.

Old R22 systems with their O-rings were designed for mineral oil.
I have helped re-fit old CFC and HCFC fridge systems with newer refrigerants
and everyone without exception leaked through all the old seals.

When we replaced the old mineral oil with the new synthetic it effected every
and I do mean every seal.

We learnt very quickly that new synthetic oil has an effect on the old O-ring so
with the refit there was a complete O-ring replacement as well.

If the system is old and the seals are old, how long have you been using Mobil Gargoyle oil?

Rob

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Quote:

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Originally Posted by Brian_UK

Does Mobil have any input on the subject ?

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Good point. Perhaps the question should be asked. Should Mobil 226E be compatible with a common elastomer such as neoprene? Probably.

I have worked on R22 system with Mobil 226E, & no real problems.
It is known that Neoprene shrinks with 226E, but usually compressor shaft seals.
All major OEM use HNBR in all new compressor shaft seals, suitable for all common refrigerants.
Mycom used to use Viton in R22 compressors.
All “0” ring charts point to Neoprene.
EPDM have never used, but thought no good with oil.
If you buy neoprene “0” rings get Parker or reputable brand in a marked bag.
Cheaper “0” rings have no traceability.
Maybe a few upgrades need to be carried out with newer components.
As stated Mobil might be able to help or someone like A & B seals in Australia

Quote:

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Originally Posted by Rob White

.

I might be wrong but Mobil 226E oil, is Gargoyle Oil. A synthetic oil.

Old R22 systems with their O-rings were designed for mineral oil.
I have helped re-fit old CFC and HCFC fridge systems with newer refrigerants
and everyone without exception leaked through all the old seals.

When we replaced the old mineral oil with the new synthetic it effected every
and I do mean every seal.

We learnt very quickly that new synthetic oil has an effect on the old O-ring so
with the refit there was a complete O-ring replacement as well.

If the system is old and the seals are old, how long have you been using Mobil Gargoyle oil?

Rob

.

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Hi Rob,
I worked for a commercial fridge company when 134a and 404a came on the scene and yes we had plenty of leaks until we started rekitting/replacing components with rubber seals during the retrofit. I have that tee shirt too!
These systems I'm referring too have been running on Mobil 226E for as long as I have been involved with them which is a while:) and the O ring seals I'm referring to have been replaced within the last 10 years.

I'm beginning to wonder firstly if all Neoprene is created equal, like maybe there this lesser quality Neoprene that is cheaper and more readily available, Parker recommends C0873-70 so i will have to see what our supplier stocks. Secondly as these systems are old perhaps there is some sort of chemical decomposition happening? They do have a unique smell to them when open but not unlike any R22 system that has run hot.

I have had feed back from an OEM who has stated the the O ring material they use is an "elastomer and neoprene compound"

Quote:

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Originally Posted by RANGER1

I have worked on R22 system with Mobil 226E, & no real problems.
It is known that Neoprene shrinks with 226E, but usually compressor shaft seals.
All major OEM use HNBR in all new compressor shaft seals, suitable for all common refrigerants.
Mycom used to use Viton in R22 compressors.
All “0” ring charts point to Neoprene.
EPDM have never used, but thought no good with oil.
If you buy neoprene “0” rings get Parker or reputable brand in a marked bag.
Cheaper “0” rings have no traceability.
Maybe a few upgrades need to be carried out with newer components.
As stated Mobil might be able to help or someone like A & B seals in Australia

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Thanks, all good points.
According to the Parker O Ring guide HNBR is unsatisfactory with R22 yet like you I have installed with no issues. With static seals O ring swell is not a problem, better than shrinkage as long as the elastomer doesn't break down.
Its a tough situation, a site with a limited life therefore low spend yet constructed with about 350 potential leak points from O rings.

The 226E oil has been a real problem for us over the years even forcing us to change entire systems to a Mobil mineral alternative Arctic 300.

Superfridge,
I think Parker Neoprene best option.
There is a Military grade neoprene, but probably not common.
Seal company used to get them from UK.
Petro-Chem would want traceability, so use Military grade.