Turbine oil sweetening

Hi,
when you look at RUL% number for remaining antioxidants, it is important that this shall be part of a trend analysis program (with oil sampling frequency at 3-4 times/year). Consequently, as international standards are specifying, ASTM and DIN, once you reach the condemning limits for one of the parameters, in this case the antioxidants, ASTM D-4378 specifies 25% alarm level, you can take some actions long before this 25%. In your case, you should perform additional testing such as particle counting, colorimetric (varnish) patch test, viscosity, etc... and than talk to your oil company to ask for their advise if you want to sweeten this oil reservoir. Experiences has shows us that with those low levels of remaining antioxidants (and possible other alarm oil parameters) you may more harm your equipment than salvage it. If you send me your e-mail adress, I can send you a copy of an interesting paper on the pro and contra's of sweetening.

Hi Jo
What is your email address? mine is: Frank.Cabello@bluescopesteel.com

Hi macabf,

I agree with Jo, you need to also get a TAN and RPVOT done on the used oil to determine how much the oil has deterioated. In general, if the TAN has increased by 0.3 to 0.4 mgKOH/g over the new oil and the RPVOT is at 25% of the new oil, it is time to change the oil. You may also find that as the oil gets closer to the end of it's life the rate of change in RPVOT also increases. Additives used for turbine oils has somewhat changed over the last few years. The old style product had the R&O inhibitor as a separate additive whereby sweetening the system with "over treated" drums of turbine oil could be done. However, nowadays most additive packages come as one combined pacakage making sweetening difficult and ineffective. Your oil company will be able to tell you if you can sweeten the system or not and advise you based on the oil analysis results.

quote:

Originally posted by Jo Ameye:
If you send me your e-mail adress, I can send you a copy of an interesting paper on the pro and contra's of sweetening.

I find it regrettable that you have chosen to offer sending the info individually instead to post it and share it with the rest of board’s members. Also, I see a trend recently where some other folks practice the same. I don’t know what to make of the fact that in the same time all of you welcome and like when others provide links to their offered info. Is selfishness the reason? Is it a sale pitch attempt? Or is it something else? I simple don't get it!

quote:

Originally posted by John Micetic:
Hi Frank,

Personally, I was never a fan of the RULER, for simple reason that no manufacturer or blender of turbine oils ever even mentioned those parameters in their spec sheets. It is something that every user needs to establish for their own oil, and it would be valid as long as they use the same type of base oils and the same type of blended additives. If the oil type was changed or different oil with different additives is used as a make up oil, the whole established process is useless and should be started anew.

However, in you case, where you seem to have established your RULER parameters, as long as you use the same oil (type and additives) as a make up oil, or use it as a sweetener, it may work for you. It is almost impossible to tell how much “sweetener” (new oil) you need to add. You may start with adding 20% of new oil and do the testing (it wouldn’t be a big deal as the RULER is pretty cheap test), and then go from there.

In any rate, I don’t mind spending a bit more and track serviceability of turbine oil by well established RPVOT, AN, and other parameters, as ReneWA suggested.

In my opinion, the scare mentioned by Jo Ameye (that you can do more harm then good with sweetening) would apply only if your new “sweetening” oil is not fully compatible with your in-service oil. Otherwise, it is a viable option for you.
Good luck.

John
See below other results from tests carried out over a period of 4 weeks, during that time we connected a Kleentek machine which helped in reducing particle contamination and oxidation by-products.
We are looking at sweetening the oil in the 6,600 tank, the plan is to drain/add 1x205 litre drum per day to raise the antioxidant level to 25%
New oil contains 0.25% phenolic and 0.25% amine
also 80 ppm zinc which currently is down to 29 ppm.

Purification of turbine oil system

23 Turbine Blower..............UIN 5C2D5........UIN 3FBD1................... Electrostatic liquid cleaner
6,500 litre tank............................................................ Kleentek ELC-R100SP
............................................................................ 12L/min

Sequence #......................................1...............2...............3...............4
Date of Sample..................New oil.........29/06/2007......16/07/2007......23/07/2007......30/07/2007
Hours of Filtration.............0...............169.............408.............574
Gravimetric Patch
0.8 micron wt mg/100ml..........<1..............3...............2.7.............1

ISO Cleanliness code............18/15/10........23/22/18........19/17/11........15/13/11........17/15/11
Particle Count
# of particles >4μ..............1312............48292...........4302............286.............663
FTIR Oxidation absorbance units.4.5.............5.8.............6...............5.9.............6
TAN.............................0.23............0.31............0.31............0.29............0.28
Ruler - phenolic................................................................7%
......- amine...................................................................11.2%
RPVOT...........................310.............107
Ultra centrifuge................1...............4...............6...............5
Colour..........................L0.5............L6.5............6.5.............6.5.............6.5
Viscosity.......................66..............66..............66..............66..............67
Zinc............................82..............29..............27..............33..............29
Sulphur.........................684.............1390............1619............1402
Phosphorus......................129.............120.............118.............132.............129

Demulsibility...................41-37-2 (20)
Corrosion.......................1a
Foam......-sequence I...........300-0
..........-sequence II..........10-0
..........-sequence III.........70-20

Hi macabf,

Please note that I am not suggesting that there is a correlation between RULER with RPVOT and TAN as stated by John. My suggestion is to rely on the RPVOT & TAN results and other test parameters for evaluation similar to the ones you have listed.
I can see that you are in Australia, most turbine oils formulated are using a combined additive package.
You should talk to your oil supplier about getting further analysis on the used oil for the antioxidant package on the FTIR. Antioxidant additives such as butylated hydroxy toluene are often used (the phenol you are measuring in the RULER method is most likely part of the BHT as it does contain the phenol group). The FTIR can identify and measure the antioxidant level of old versus new oil, a calculation can be done to determine the amount of top up you need to bring the antioxiant level back up.
However, the success of sweetening is dependent on if you have been topping up with the older style formula or the newer style formula over the years. This may be a reason why you have seen a change in the zinc level as the formula may have changed over the years.
To find out if this is the case, you should talk to your oil supplier.

There was a series of papers presented at ASTM in December 2005 showing RPVOT was very accurate for oils using BHT/DBPC (oils RPVOT was developed for) but was not as useful for turbine oils using amine/phenol combinations. Basically when the phenols depleted, the varnish/AN started accumulating even though RPVOT was still in good shape since amines just starting to deplete. Also some of the newer antioxidant systems are acidic causing AN to decrease with initial use followed by increase.
Are you monitoring a steam or gas turbine? When were the RPVOT performed: 2 data points/5 dates? I am not that familiar with particle counts but it looks like you had a very high particle count prior to cleaning with the electrostatic cleaning but the particles started to increase again during the last sample or is increase within reproducibility of test?
I copied the below response from the bottom of page 2 of this forum when sweetening was also discussed. Gives a link to get some of the data that was presented at ASTM.
Rick - Our paper presented at ASTM Norfolk last December showed our results of 3 samples, two used turbine oils and the new oil, sent to 4 different labs, in four different parts of the world. The samples to three of the labs were unmarked to try get get some real "blind" testing results.

Of the blind labs, two of them could not even tell the difference between used oils and the new oil (by RPVOT values, of course the color would have been a dead give-away, but they must of neglected to look at that)

One blind lab maybe looked at the color of the oils, and gave results that sort of made sense, at least the new oil was higher in RPVOT than the used oils. However, they were still way off in the realive RPVOT values.

The only lab to get the results right, was the same lab than blended the oil!!And you guessed it, they were not blind, and knew it was their oil. Lo and behold, they got the new oil value right!

What does that tell you? It tells me that RPVOT does not work with true unknown samples, in true blind testing, and that most RPVOT results are made-up by random number generators or dart-boards!!
(rememeber the accountant job-applicant joke..how much do you want it to be, boss?)

email me at andy.sitton@focuslab.co.th if you want to see the data

John
I am the inventor of the RULER so I will try and answer some of your concerns. The RULER is used world-wide for a variety of systems - links to papers available at www.Fluitec.com. I believe Turbomeca a major aircraft engine company has written the RULER into its specs. SKF has developed a RULER test for greases which I believe is in the round robin stage of ASTM. There are ASTM procedures for using RULER on turbine oils.
The problem is many additive and oil companies are doing research with the RULER but don't want data given out to general public for various reasons. So personal contact is the more acceptable avenue. Second there are numereous papers being presented on RULER/turbine oils but are not published again for various reasons making it hard for public sharing. Also there are the issues of copyright forcing interested parties to get data from sponsoring organization not the author.

With respect to RULER acceptance:
My previous reply has e-mail for one of the papers presented at ASTM 2005 symposium on turbine oil oxidation symposium. Presumably you can now get electronic copies of all of the papers presented but even though its coming up on two years still not sure of availability. Several papers showing good correlation between RULER and RPVOT for phenol systems, differences occur for phenol:amine systems. RULER provides valuable information on antioxidant system so that results of RPVOT can be better understood with regard to varnish and oxidation.

NORIA Conference Louisville May 2007
Session Titled Sludge and Varnish - 4 of the 5 papers used the RULER as means to monitor antioxidants. Albemarle, an additive company, was one of the authors
STLE Conference Philadelphia May 2007 -
Ontario Power presented a favorable paper on RULER in Condition Monitoring III
Several Papers in Power Generation I and II using RULER specifically to monitor phenol replenishment. Problem is STLE allows presentation with out publication. I believe NORIA is the same.
The papers indicated the pitfalls that may occur with turbine sweetening come from adding phenol/amine combinations when only the phenols are depleting so you end up with a large aminehenol ratio which promotes sludging from amines. RULER allows you to identify the antioxidant that is depleting/needs replenishment. In cases such as this thread where both antioxidants have been depleted almost completely the phenol:amine ratio would remain intact so sweetening seems an option assuming work to restore cleanliness of oil/system is possible.

Why did NORIA put a smily face in place of amine: phenol does = face?

Guess it does. : p without space = face.

Frank,
I will give you my honest opinion about you oil based on your analysis report.

1. Based on relatively high AN of the new oil and after being in service, it seems that your oil is blended with Group 1 base oil. In addition, relatively low initial RPVOT (310 min. for new oil, when most Group 2 turbine oils have RPVOT at minimum 800, and some in range of 1200 and up to 1800 min). Also, the presence of Zinc (and phosphorus and sulfur) lead me to believe that you have ZDTP type of antioxidant, which was generally used (and probably still is somewhere) for blending Group 1 turbine oils, rather than exclusively an ash-less additive package. If this is correct, then I don’t know how reliable RULER analysis would be for you. Maybe Bob K. can shed more light to it.

2. From my experience, I have seen the initial RPVOT (new oil) drop after the oil has been in service for awhile. However, after this initial drop, RPVOT establishes itself at some lower level and remain on that level for long time. If you look at Zinc concentration, you see the same pattern – drop from initial 86 down to upper 20 level, and remain pretty consistent at that level. That also support my thought that you probably have Zn-based antioxidants. Of course, they might be some ashless-type additives added too, but they are not exclusive.

3. Your Kleentek filter works fine. The cleanliness reported on 30 Jul, showing worst code than the one from 7 days earlier, may be affected (contaminated?) during sampling & handling, or the same sampling procedure was not utilized (e.g. draining at the sample port inconsistent?). I say this because both the Gravimetric Patch analysis and Ultra Centrifuge suggest that the sample from 30 Jul is cleaner than the one from 23 Jul.

4. I don’t know what to make of you RULER analysis, but you don’t have to sweat (yet!) too much, because your RPVOT shows approx. 35% of the remaining life, and condemning limit is when starts dropping below 25% of the remaining RPVOT. I have a sense that RULER lovers think very low of RPVOT (like, it is inconsistent and not trustworthy analysis). But guess what, in RULER literature it is suggested to run RPVOT (yes, the same “unreliable” RPVOT) whenever RULER comes down to 25% level – to check for the “Remaining Oxidative Life estimation”. Some folks love to have it both ways.

5. The one thing that puzzles me is the color of your oil. In just over two weeks it turned from 0.5 to 6.5 (similar is when I do oil change on my VW Beetle TDI). This color, and the initial high cleanliness code after you filled new oil in the machine, suggest that you guys did not make a serious attempt to flush the system, if at all.

6. I don’t know if you guys ran compatibility test between new and in-service oils before you mixed them or filled the machine. Incompatibility may cause stripping of the additives, and caused such (and worst) rapid drop-off in RPVOT. For years we successfully used services of the Herguth Labs in “dodging the bullet”, by avoiding new oils that were tested and identified as being incompatible with our in-service oil. But now you, and everyone else, can use new, and first time ASTM assembled method for testing compatibility, ASTM D 7155-06, Standard Practice for Evaluating Compatibility of Mixtures of Turbine Lubricating Oils".

7. You did not post numbers for water in oil. I don’t know of what kind media you filter is made from, but a great performance we are getting from the cellulose type filters (like what the CCJensen and others offer). They are absorbent filters, and therefore, besides capturing particles, they take care of small amounts of water in oil, if it gets there. Of course, if there is a cooling water leak or other types of water ingression, that water should be dealt with a demoisturizer. However, if your Kleentek is not an absorbent type, you can always add an absorbent scrubber to it

8. According to the viscosity, your oil is at great shape. My suggestion would be to keep that Kleentek running 24/7. Your cleanliness will look better and better, and you might even enhance the color of oil. Also, it should be of no surprise to anyone to see RPVOT reading higher once the oil is cleaner. It has been noted in literature, and from my personal experience, a high load of contaminants can cause an early (premature) pressure drop during analysis, thus showing lower RPVOT than actually is. After filtering such oil, it showed better results (higher RPVOT). Also, keep an eye on AN and cleanliness (once in a month would be sufficient but you can do more often if that would give you piece of mind), and check RPVOT every 6 months until is stabilized. After that time, you can test it just once a year as long as AN stays fairly consistent. As a footnote, our AN warning limits for Group 1 turbine oils is at 0.5, and condemning limit at 0.70, providing that the initial AN (new oil) was 0.20 - 0.25.

quote:

Originally posted by Bob K.:
...With regard to ZDDP, I thought RPVOT should not be used on oils containing ZDDP - pressure drop affected by ZDDP/water decomposition gases...

Bob, RBOT has been used for ages in reliably assessing serviceability of turbine oils; for decades before any of the phenol and amine type of additives were ever introduced. Also, for long long time ZDTP was the only type of antioxidants used in blending process. If that is true, are you saying that the whole industry lived in a la-la land by naively trusting this analysis, for which you say that it is unreliable for oils with ZDTP?

Also, if Frank or others out there that use turbine oils blended with ZDTP, then why not you or somebody else tell him (and others in similar situation) that tracking amine-phenol ratios in such case might be rather marginal, because such oil might not have sufficiently broad base of these additives necessary for the serviceability evaluation? If there are no amine-phenol-based additives in his oil (or just small quantities being present), instead of amine-phenol ratio, what should he be tracking by RULER?

Gents
The oil is group I and latest RULER results are: phenolic=5% amine=0% ZDDP=5%
TAN new=0.23, current=0.28
Gravimetric patch 0.8 microns wt mg/100ml=0.8
Particle count=15/13/11
RPVOT new=310 current=105
Ultra centrifuge new=1 current=5
Viscosity new=66 current=67
Colour new=0.5 current=6.5

Based on RULER results according to ASTM D4378 (Warning limit 25%)and low RPVOT we will sweeten the 6,600 litre tank with 2 x 205 litre drums of new oil, one in the morning and one in the afternoon.

Kleentek machine (12L/min) has done a wonderful job of improving oil cleanliness after 574 hours running, judging by the Gravimetric test results of before=3 and after=0.8
and particle count before=23/22/18 and after=15/13/11 (It has done nothing to improve ultracentrifuge or colour like I hoped it would).

This system has coarse filtration but will be fitted out with a CC Jensen 3 micron filter prior to changing the oil in mid September 07

Thanks for all your imputs, it certainly created a bit of interest.

We will monitor the antioxidant level a week after drain/adding the new oil which has not change in formulation except for the origin of the base oil.
Frank

Bob K.,

Thank you much for jumping in and offering help to Frank. Especially, because the RULER is “your baby”, which makes you being the right person to do it. He appears very enthusiastic and is trying to do the right thing, but seems slowly getting lost in trying to find ways to interpret RULER result. I think that folks at the lab that Frank was using obviously did not do much for him, except sending him dry test data. Is it my impression that they don’t know much about it, except just running the RULER analyzer.

As I mentioned before, (some folks wouldn’t believe it!) we have some oils that are “older than dirt” (some are 40+ years oil and still in service). More typical age is 25-30 years in service. How authentic those oils are it is hard to tell, because our folks added a lot of make up oil to it during those years (somebody shout SWEETENING). We also have powerhouses running new Group 2 oils, too (the ones that changed their turbine oil in the last 10 years). So, of course, we still have some oils with ZDTP in it. Do we have phenolic-based additives too? It could very well be the case, because we added over the years make up oils that may have had these types of additives. Unfortunately, I could not be more specific because I am not a blender nor have I ran RULER or mass spectrometer to check it out. However, we simply relied on RPVOT in combination with other characteristics to assess remaining service life of our R&O turbine oils. It has been working flawlessly and reliably so far, and for that reason I am not “hot” about RULER at this time. By the way, we have approx. million and a half gallons of turbine oil in our powerhouses.

I am a novice in the oil analysis world so forgive my basic question that is: what is the difference between AN, BN and Ruler and what is best for what oils, or does it depend on your oil type?

quote:

Originally posted by Andy_Sitton:
Here's a case of RPVOT vs Ruler trivia for you all....

EUREKA! I solved the trivia! The answer is: "If anyone have oil problem, contact Andy Sitton, cous' HE IS THE KING". And we all should just ignore whatever oil conpanies' labs are telling us, because they are just a bunch of boneheads! Correct?

quote:

Originally posted by Andy_Sitton:
I think here is the point that most folks are missing; that a good RPVOT result, by itself, does not mean milk and cookies !!! Even if you are the King !

I think this is baseless assumption, because majority of folks on this board handle lubricants or lubricating issues on a daily basis, and they are certainly aware of the point that you are trying to make. I wish you would show a bit more respect to them (myself excluding). Personally, if RPVOT test shows the remainder of antioxidants of below 25% in my oil – I am changing it, regardless what would KING come up with his RULER.

Also, nobody that I am aware argued here that if RPVOT is OK than the oil must be OK. Or maybe I misread the tread?

Bob
The oil was last changed in 2003 and the RULER tests started in 16/7/2007 when we notice a drop in RPVOT=107 or 34%
It's a steam turbine, and the oil contains 85 ppm of zinc when new.
New oil is very light in colour like straw (not green.
Demulsibility new=41-37-2(20)current=40-40-0 (30)
Foam
-sequence I =300-0 current=440-5
-sequence II =10-0 current=30-0
-sequence III=70-20 current=480-10

Are you saying that the amine is removed by the Kleentek oil cleaner?
Frank

No, John, I am not saying I am the King...I was quoting comedly from a Mel Brooks movie....sorry for trying to break up the seriousness and animosity of the tone...I am hereby out of this message board chat...satisfied?

Frank
Couldn't get on-line yesterday, our IT personnel installed some new patches Wednesday nite - create 2 problems for everyone they fix. good way to ensure job security
As far as I know Kleentek or any other filtering system, electrostatic or physical doesn't remove soluble additives such as amine or ZDTP. However, if you have polar sludge, the polar alkyl amines will coat the sludge and thus be removed from the oil when the sludge is removed.
Trib. Trans. 47 pp.111-122, 2004 Yano,Watanabe, Miyazaki, Tsuchiza and Yamamoto, "Study on Sludge Formation during the Oxidation Process of Turbine Oils" ran 20 different turbine oils with dry TOST at 90 and 120C, pulled samples at set time intervals, ran RBOT and sludge (couldn't find pore size). Two oils had ZDTP. Rest phenol and/or amine based. Oil C had RBOT 350 hours, ZDTP, 1400 S and 59 ppm Zn. Oil F had 595 RBOT hours, 600 S and 59 ppm Zn. Authors stated ZDTP had poor sludge resistance - exceeding their sludge parameters when RBOT life was still 70%. They found sludge was primarily Zn sulfate. Oils C and F sound similar to yours and their research would help explain why Zn levels drop with usage - not sure why your sulfur went up. Would think alkyl amines would be attracted to Zn containing sludge.
I am still puzzled as to why ZDTP would be used in turbine oils but stand corrected.

JonnyC
Basically during use, antioxidants in oil deplete, when antioxidants reach around 10 - 20% of original concentration, oxidation accelerates and carboxylic acids (AN)accumulate and oil basestock starts to polymerize (viscosity increase/varnish formation).
In combustion engines, the oils contain additives (BN)to neutralize combustion gases. Some high temperature hydraulic fluids also have additives to neutralize strong acids from additive decomposition - basically independent of oxidation. So BN is only useful in systems that create strong acids.
RULER is an on-ste instrument that primarily measures antioxidants - FTIR, LC and other laboratory methods also available.
AN/BN are usually done by titration on-site or in lab although RULER and FTIR non-titration methods also for AN/BN.
The time from when the antioxidants deplete until AN increases is application dependent. The higher the operating temperature, the shorter the time until AN exceeds limits. So for low temperature applications with big oil reservoirs, the time between antioxidant depletion and AN increase can be months/years. For higher temperature systems, the time between depletion and AN increase can be days.
As with any oil condition trending program, you have to develop some history to understand the degradation mechanisms so that you can determine which technique is of most value. RULER is predictive/can detect abnormal conditons early on (once antioxidant depletion rate established can extrapolate to predict future readings such as when the oil will break)while AN is reactive (can't predict when oil will break)has been around for a very long time and most applications have well established limits for safe usage although recent changes in basestocks and antioxidants are requiring that some established limits and capabilities of other techniques be revisited.

Bob K.
You're a star. Thank you very much for the info.

All
I have notice that the Kleentek oil cleaner has actually lowered the TAN from 0.31 to new oil condition of 0.24 has anyone an explanation for it?
Frank

Various papers state that varnish contains carboxylic acids so varnish removal would be expected to lower TAN.
Just curious, what type of repeatability do you have on your TAN measurements?

Hy John,
I`m looking for materials who talk about TOST, RPVOT, and what test is more representative. I used in my hydraulic system the Mobil DTE 26 but some friends think Tellus 68 is best. Can you help me?
Thank you!

Dear all,

I need your help to interpret the results of a Foam Test ASTM D892. We detected foaming in the exciter bearings (its is visible in the sight glass). This was detected after a turbine trip due to high vibration in one of those bearings, however, we don’t know if the foaming started before or after the trip. I decided to immediately do an oil analysis for particles count, water content, viscosity etc and for this time (we normally don’t do this test) a foam test ASTM D892. The analysis results were:

Oil: Super Turbo Flow 32 (ISO 32) Petrocanada Turbine Oil.

ISO Cleanliness: 17/15/11 >4μ = 1016, >6μ = 200
Water KF PPM: 26
Wear Metals: Fe = 0 PPM, Ni = 0 PPM, Al = 0 PPM. Cu = 2 PPM
Contaminant Metals: Si = 0 PPM
Additive Metals: Zinc = 1 PPM, Phosphorous = 88 PPM
Viscosity at 40 oC: 35 CS
TAN: 0.03

Foam test ASTM D892

I (5 min blowing) 260 mL
I (after 10 min settling period) 0 mL
II (5 min blowing) 30 mL
II (after 10 min settling period) 0 mL
III (5 min blowing) 50 mL
III (after 10 min settling period) 0 mL

I was very happy to see the good numbers for particles, viscosity, water content etc. Since all of them would indicate that the foaming problem is not the oil but mechanical issues in the turbine bearings or lube system. However, in the case of the Foam test I am not so sure. The fact that after each settling period the foam count was zero is very positive but I did not expect to see such high value of foam forming in the first sequence (260 mL). I called the lab and to my big surprise and disappointment they look to be as clueless as my self about whether the 260 mL was too high or not. Under pressure they finally accepted to do some research and came back to me with an answer. I paste their answer below.

The outsource lab called me back with the reruns results they are still within the test’s repeatability. According to ASTM D 6224-09 Table 3 Warning Levels of In Service Oil Test. Foaming characteristics, Tendency >450 are a fail and <450 are a pass. As a testing Laboratory we recommend that you contact your Lubricate Distributor to address the oil’s forming characteristics. Please let me know if you have any questions.

Could you offer me some advice on this topic? Can I trust my lab advice? I am thinking in the possibility of changing the lab we use.

Thanks in advance for your help.

Dear Cristian,

Thanks a lot for your reply. It was of course very useful. In this case, no we have not added any oil to the turbine for a while. So the foaming cannot be becuase of new oil or additived being add. I also want to remark that our foaming problem is not that severe. There is foaming visible in the sight glass of the exciter bearings, which was not there before, but there is none in the oter bearings and in the oil reservoir. It is interesting what you mentioned about the Phosphorous because that is a recurrent problem in our oil analysis even in the new oil sample. I did not give to much importance to that because it was not affecting anithing at least that we know of. However, I will contact our oil supplier and ask them about this. Thanks again.

I'm fighting a foaming issue now.

My oil is NOT cross contaminated. We're a nuclear unit, we have VERY good records. Plus, I am running every test under the sun on it.

All of the standard tests come back acceptable.

Yet, I have foam. Not to the level of seeing vibration issues, but it's there.

I'd be interested in what type of oil you are running. Have you recently changed to a group II base stock? Maybe without even knowing it?

I'm seeing very, very slight foam levels in other reservoirs too. Mostly running R&O oils.