Oil Loss and Recovery Problem in Centrifugal Chiller

[Mechya]

I am experiencing Oil loss and Oil recovery Problem in a Centrifugal Chiller, Capacity 1000 TOns. Oil level in the sight glass disappear within 10 to 15 minutes of the chiller operation. Can anybody advice me on the causes, Thnaks in advance.

 

[briand2]

I suspect your oil is migrating to the evaporator...

 

[Mechya]

Thanks braid2, this has happened, I drained the oil from the evaporator, but i would also like to know why the oil is not returning to the oil sump, is it a mechanical or operational problem?. To further explain my situation, chiller is Semi Hermetic Centrifugal Chiller with R-22 Refrigerant. r there ways to recover the oil and bring it back to the oil sump.
Thanks.

 

[cme]

R-22?

What manufacturer .........

 

[tombmech]

Carrier built an entire line of R-22 centrifugal machinery in response to the 1990 Clean Air Act, the phaseout of R-11, and before R-134a had been totally accepted (oil miscibility problems, and they also had to tool up for ASME Stamp manufacturing capability). This lasted for a couple of years or more, then the total switch to R-134a was made. Carrier refused to change to R-123. Trane had not ratcheted up the political lobbying for R-123 initially, and was busy solving dissolving gaskets. They had decided that the hurdle of ASME Stamp production was too great, and decided to cast their lot with R-123 (still a low pressure refrigerant). There was just a small problem with it dissolving gaskets.

Unlike R-134a, however, R-123 first had serious Threshold Exposure Limits (why SCBA's are needed for leaks), and is still not free from Ozone Depleting Capability. However, once the lobbyists for ASHRAE and EPA tooled up, now we have ASHRAE Std 15 requirements that force refrigerant leak detectors and emergency ventilation in both cases, and the EPA "recognized" that stop-gap refrigerants were OK. Or, that the potential for high-pressure leaks of R-134a was just as dangerous as the health effects from R-123 (no one pointed out that R-22 had been around for decades). Eventually, even "Global Warming Potential" labeling was applied to R-134a cans in the Auto Parts Store - a perverted success of the lobbying effort.

It is interesting to note that global warming potential labeling has nothing to do with the R-134a gas itself. However, the refrigerant process with R-134a is slightly less efficient - inherently - so its use in refrigeration machines burns more energy which causes the release of more CO2 at the power plant(!), hence global warming. So, the can is labeled as such because of this seriously stretched logic (not really true anymore, anyway).

Meanwhile, releasing a can of R-134a into the atmosphere has zero effect on health, zero effect on Global Warming, and zero effect on the ozone.

It's a funny political world we live in. NOT.

Anyway, to answer your question - yes, there are some Carrier R-22 centrifugals around - maybe others I'm not aware of, too.

 

[joeywpittman]

what is the model number?

 

[joeywpittman]

Make sure the oil is at the proper temperature for this machine. At temperatures lower than this, oil tends to absorb large amounts of refrigerant, which is held in solution until the oil is agitated or heated. Oil that is cold and saturated with refrigerant will cause foaming in the lubrication system. The foam tends to migrate to the evaporator.

 

[joeywpittman]

http://www.xpedio.carrier.com/idc/groups/public/documents/bulletin/c9321.pdf

 

[joeywpittman]

RAPID OIL LOSS:
If the oil is being lost rapidly (within a one hour span), then an inspection of the internal
components of the machine may be necessary. The following components should be
inspected for leaks, missing parts, or proper clearances:
1. Oil reclaim check valve
2. Demister vent line filter
3. High speed thrust assembly o-rings

 

[Mechya]

Thanks very much Mr. Joeywpittman, temperature is well maintained as recommended by the manufacturer, but sometimes the load on the machine is in the range of 50 to 60 % of the machine capacity, can this be a contributing reason ?. As you rightly pointed out and as I mentioned earlier that the oil loss is very rapid, the oil level in the lower sight glass disappears within 15 to 20 minutes of the machine start, either I have to charge the oil contineously to monitor the operation for some time or shut the machine off.
We have opened the machine and replaced the mechanical seal on the rear end bearing, the high speed shaft seal and the thrust bearing oil rings.
I already checked the oil reclaim check valve also, its fine.
I did not checked the Demister vent line filter, may be i will have a check for this as well...
Anything more to solve this problem from the experts is highly appreciated.

The Machine is 19FA Carrier Model.
Thanks..