Plugged filter drier

[Webber]

Our customer claims oil is plugging his filter drier. They are currently running a split system (10 ton nominal) with a rotary compressor and oil separator. The oil separator is rated at 98% efficiency. The system is running on R22 with Sunesco 3GS mineral oil. I have requested a sample from the liquid line to determine oil carryover in the system.

Any ideas on how the oil is getting into the system? Any similar incidents of oil-plugged filter driers?

 

[pennpoint]

Webber
There is always some very small amount of oil carry over. But plugging the filter/drier! I do'nt think so.
You should be able to determine if the filter drier is plugged by measuring a difference in upstream and downstream pressure or seeing bubbles in the sight glass.
What makes the customer think the filter is plugged?
Maybe the filter is installed backwards?

Regards
pennpoint

 

[Webber]

Excellent points Pennpoint!!

I asked the same questions. The claim of oil plugged filter is coming from the filter manufacturer. The pressure transducers on either side of the filter indicated a high pressure drop in the filter. There were some copper filings (result of poor installation practices) but the determination from the manufacturer was plugged with oil. I too find it very hard to believe.

 

[pennpoint]

Webber
Well I'll be...
Ok! I can imagine plugging with oil sluge or something like that but not plugging just from oil. It should'nt accumulate there.
I've seen large amounts of carryover in systems but it never plugged a filter.
I hope to learn something with you here.

Good Luck
pennpoint

 

[ClydeMule]

I agree with pennpoint, and wonder, why do they think it is plugged with oil? Actually, what is the problem, that made them or you ask the manufacturer whether or not that it is plugged with oil?

Also, did the filter drier mfg tell you that the FD was plugged with oil, or did they tell your customer that? If they told your customer that is it possible they misunderstood?

Not that it can't happen, but I have never heard of an FD plugging with oil. It is miscible with the liquid refrigerant. Like pennpoint said sludge maybe, oil not likely. The fact that there is a separator makes it even less likely. Unless of course the separator is not installed properly.

Just out of curiosity, what is the application? Not very often do you see a 10 ton split with an oil separator. What kind of compressor (mfg?).

Clyde

 

[Webber]

ClydeMule,

I am with you both. This is puzzling to me also. The mfg of the FD relayed the information to my customer, so it is possible (and very likely) there is a misunderstanding.

The application is for commercial and residential cooling (test facility of 10 prototype units) in Las Vegas. Ideally, they would like to provide a packaged system, but worst case would be split systems.

The compressor used is a RotoVane rotary compressor. It does not have a sump like your typical recip compressor, so the oil separator is required to act as the sump and to maintain oil control at the compressor.

I have contacted my customer for more information. I will keep you both posted with any updates.

Thank you both for your support and interest in this matter.

 

[pennpoint]

Webber
What type of oil sep is used? swirl/drop-out or coalescing?
Maybe its too small, causing lots & lots of carryover.
Do you think the FD is sized properly?
Could it be overcharged with oil?
As ClydeMule guessed regarding miscommunications, now that your in there you need to be one on one with everyone so you hear it right.
"RotoVane" very interesting.

Post any conclusions

pennpoint

 

[imok2]

If this was a poor installation an copper was found then it's possible the installer didn't use an inert gas when the system was made up thus creating a large amount of carbon on the inside of all the brazed joints, if thats the case then all you can do is keep changing our the filter driers until there is no appreciabe pressure drop

 

[ClydeMule]

Webber,

Are you then engineer, installing contractor, both? I am going to be in Vegas a lot the next couple of weeks, was just there yesterday taking care of a customer.

This system sounds interesting, I would like to check it out. Any chance of taking a look when I am there? Give me a call or post a reply.

Thanks,

clydemule

Johnson Thermal Systems, Inc.
760-489-9920

 

[Webber]

ClydeMule,

I represent the compressor manufacturer. It is a long and detailed story so I will not bore you with the details. Unfortunately, due to proprietary issues, I cannot set up a meeting for you to see the installation.

However, I am happy to discuss with you on the phone. I tried to call your number but did not leave a message.

Regards,

Webber (Norman Gillespie)
(416)456-0442