Changing from Mineral Oils (Clavus 68) to semi synthetic ( Arctic 300)

[Grizzly]

I was phoned last week by a site engineer who was having issues with his liquid ammonia pumps cavitating.
After much discussion, I asked whether he had been away recently?
As I was coming to the conclusion that his system was short of refrigerant
His stand-ins have caused issues before.
No! Was the answer.

"But I have changed oil" (Clavus 68 is no longer available as we have discussed before.)

"And I was oil draining for at least 4hrs the other day. I cannot remember when I last removed so much oil!"

When told what oil he had changed to the penny dropped.
In the past I have noted issues with Mobil Gargoyle oils.
Because they contain a cleaning agent for want of a better word. Which is very good at cleaning / scouring systems.

I have reached the conclusion that the new oil is flushing the old oil. With so much being drained that the surge drum working level has dropped to the point where the pumps are being starved of refrigerant.

I have suggested that more ammonia is added and see if the issues are resolved.

Has anyone else experienced similar?
It strikes me that changing the oil in any system can have a huge impact on how it performs.
Grizzly

[piewie]

I would recommend reverting to the 68 it is available from Canada Oil Reflo 68

[Plank!]

I would recommend reverting to the 68 it is available from Canada Oil Reflo 68

Agree with this.
Reflo also has a "detergent" property, so expect to be draining some really filthy looking oil for a while.

Steve

[Grizzly]

Thanks for the info guys.
I will let you know how things progress.
Grizzly

[Magoo]

Hi Grizzly.
CPI 1009-68 and Reflo 68A have a reaction with Buna N and viton o/ring material, recommended HSN or neoprene compound o/rings only.
The reaction is hardening then leaks, particually on shaft seals.
magoo

[Grizzly]

Thanks Magoo.
A very relevant point, I had forgotten that some O/rings degrade with some synthetic oils.
(been there as well!)
Thank You.
Grizzly

[aawood1]

Hi Grizzly, I had probles with the shaft seal "O" rings on a Howden WRV 255 MK6 after we changed the oil over from Arctic 300 to Clavus 68 about 8 years ago due to the company changing the oil supplier for the group. But on the last install of Grasso duo-packs last year we are now using Reflo 68 in them but are still able to get Clavus 68 as we use it in the coldstore Grasso RC 11 units.
Regards Arthur

[mbc]

also you can use LPT 68 from BP.

I used before ziraic 68 then moved to clavus 68 from shell Co. and now we are using LPT 68

as you Know mean things to chose oil are .

type of oil ( mineral or semi synthetic )
pour pint . flash point .drop point. ...

[Magoo]

Hi Grizzly.
OK a late comment, but have also used mobil SHC 226 and 426 synthetic oils expensive but extra long performance between oil changes, I think they are made in France. A good mineral oil is Suniso 4SA.
magoo

[sterl]

These pumps cavitating during a re-start from standby?

With the amount of oil that suddenly started moving: A low temperature centrifugal pump starting half or more full of oil won't "prime" at all; cavitates unless the whole assembly heats up enough to blow the oil through. High pump rotor speeds aggravate this and they will often trip on high motor current after egg beating cold oil for a few seconds....

[TXiceman]

I have seen problems going from mineral based oil to synthetic oil before. You need to really flush the oil oil well and then probably do another oil change in a month. Some of the additive and anti-foam packages do not mix well.

Ken

[Grizzly]

Thanks for the input Ken.
I did say I would update everyone, only there are still issues.
Time will resolve them, the irony is that we have a wholesaler that is still supplying Clavus 68.
This particular customer sources his oil himself and what he has has come from "Others!"

Ken.
What you are advocating with the oil change option is understandable.
But the design of this Ammonia plant (and age) means that would not be practicable, however as some have mentioned.
Given the oil drain frequency eventually all the old Clavus will flush out.

I originally raised the issue because like yourself and others.
I too have seen and dealt with various issues resulting from such an innocent thing as a change in the oil used.
The oil used and it's effect upon a system will still be a issue for many, for a long time to come.
It used to be simple pre synthetic oils, not any more!
Cheers Grizzly.

[Magoo]

Hi Grizzly.
FMC do what they call a semi-synthetic oil, possibly a good option for transtion from mineral. I used it in China with no detrimental effects or issues. Just a thought.
magoo

[mbc]

Hi grizzy

why you want to move for Semi-synthetic oil?

Semi-synthetic is expensive than mineral oil , also in old and large system you have a lot of in system, to to drain them it is difficult or we could say almost imposable. some compressor manufacture does not recommend to do that and some of them does not answer you .

also in large system we change oil compressor every 1000 h in (R 717) NH3

But if you want to do that I recommend first you test it. HOW?
you have mixed old oil with NH3 (from oil drain ) mixed it with your new oil and put it in different temperature +50( condenser temperature) and then near pour point (( I think pour point for Clavus 68 is about -30 )) so -25 for for 2 or 3 weeks and then check the mixed oil, how is that ? special acidity of oil and those it comes greasy or it has good condition . then go further.

changing type of oil in semi hermetic system ( close system ) is risky with out getting permission form compressor manufacture.

[Grizzly]

MBC.
Please read the original posts before replying!
No-One wished to move from Shell Clavus 68. Its production has ceased and and the choice of an alternative was being questioned.
If you followed my posts you would know your further kind advice is unnecessary and has already been discussed.

Yours must be a wealthy company to change the oil after 1000hrs running. What manufacturers state such a short run time.
I ask because I have never come across one?
Surely as I state with the old plant that I am describing which is regularly being drained of carried over oil.
That process itself will eventually flush the system.
please read the posts.

To add!
You just may not have understood completely because unlike me you are not using your native tongue.
That being the case please try and remember "We" can only respond as the posts are read.
Grizzly