CVH OIL SEAL ISSUES

[acjourneyman]

Anyone else order a new oil seal lately and have problems.Ordered one as the old one is .012 and the new one is a tight .002, screwed up the day and have to early am another one in, one of our guys had to go through 3 to get one to fit. I would advise if you change one to check it on dissasembly so you have time.

[txhvac]

Anyone else order a new oil seal lately and have problems.Ordered one as the old one is .012 and the new one is a tight .002, screwed up the day and have to early am another one in, one of our guys had to go through 3 to get one to fit. I would advise if you change one to check it on dissasembly so you have time.

.002 is a tight fit (.004-.007) I personally have not come across this as of yet. Aren't you an OEM? What's LaCrosse have to say? Interested in reading other posts.

[jayguy]

Anyone else order a new oil seal lately and have problems.Ordered one as the old one is .012 and the new one is a tight .002, screwed up the day and have to early am another one in, one of our guys had to go through 3 to get one to fit. I would advise if you change one to check it on dissasembly so you have time.

i would agree that 2 is quite tight and that 12 is pretty loose. i have not ordered one in years. good advice in measuring during disassembly...sounds like andreson advice!

[triggerhappy]

Anyone else order a new oil seal lately and have problems.Ordered one as the old one is .012 and the new one is a tight .002, screwed up the day and have to early am another one in, one of our guys had to go through 3 to get one to fit. I would advise if you change one to check it on dissasembly so you have time.

I prefer to burn mine in.

If you feel it is to tight put some neverseize on the teeth and burn it in.

[ga1279]

Just a quick question : Is that Trane's new and improved nylon seal ?-GEO

[triggerhappy]

Just a quick question : Is that Trane's new and improved nylon seal ?-GEO

That would be a spacer seal.

[acjourneyman]

Yes, it was the new aluminum seal, no drain hole in it. I had a hard time getting an .002 shim in it so it would have rubbed, hope the one I get on monday is at least .0035 and yes , i am OEM. Lacrosse thought it was a little tight, I just am wary of rubbing as I have seen grooves in shafts from aluminum seals.

[ga1279]

I was mistaken. I have had the oil seals come from the factory .002 and less. I won't try to rub, sand or file the clearance. Instead if Trane won't remedy the situation, the seal goes to the machine shop with the critical shaft diameter measurement taken at 8 points 45* apart. Trane of course won't pay, but the cost has already been built into the bid, sort of. I know of one case when the oil drain was still present and I was told by an engineer from La Cross the drain could be installed in any position and it didn't make any difference. While we are on the subject of Trane's, seals and oil, why does Trane allow the oil in the later versions of CVHE's and CVHF's to run at such a low temperature while the chiller is in operation ? I have seen them run down to 95*F before the oil heater energizes. I have taken oil samples from these chillers and by the time I get the sample to the lab I'm down to 1/4 of my sample. If that's the refrigerant content in the oil it has to be wiping the bearings. What do you think ?-GEO

[Doesn'tPhaseMe]

Yes .002 is tight but here is what I'm thinking. If it is not causing any problems with binding the shaft up do you think it will cause any problems associated with oil loss? I don't it is a non contact seal and if anything it will further minimize any loss compared to excessive clearence. Also it would probably wear in rather quickly too once running and being a lot softer than the shaft I don't think that would pose a problem either. I would make some calls to the factory and my supervisors explain my thinking and see what they say. Yes it is not within factory spec but maybe really not that bad.



While we are on the subject of Trane's, seals and oil, why does Trane allow the oil in the later versions of CVHE's and CVHF's to run at such a low temperature while the chiller is in operation ? ...... What do you think ?-GEO


Because they are shutting off the oil heater during operation to enhance their kw/ton rating. They do this on the UPC2 and newer chillers. If it is a problem there is a different chip that can be installed in the UPC2 chiller module that will allow oil heater operation while running and will give you a set point for it. On the Dynaview there is an option in the machine configuration that to allow this also and then it will give you a setpoint for it on the setpoint screen. Also if your tower water is running on the cool side that will cause your oil to run cooler since the oil cooler is in the economizer especially with lighter loads too. I think with the chiller and oil pump running it will agitate the oil and help keep the refrigerant out too.

[txhvac]

Because they are shutting off the oil heater during operation to enhance their kw/ton rating. They do this on the UPC2 and newer chillers. If it is a problem there is a different chip that can be installed in the UPC2 chiller module that will allow oil heater operation while running and will give you a set point for it. On the Dynaview there is an option in the machine configuration that to allow this also and then it will give you a setpoint for it on the setpoint screen. Also if your tower water is running on the cool side that will cause your oil to run cooler since the oil cooler is in the economizer especially with lighter loads too. I think with the chiller and oil pump running it will agitate the oil and help keep the refrigerant out too.

I agree w/DoesntPhaseMe. There is also the enhanced oil temp. protection option in the FSU menu-oil heater comes on @ 140 temp and satisfies @ 145, the low oil cut out is setpoint is sat.evap temp plus 30 or 100 which ever is larger. Has to be enabled if you have the refrigerant pump. I've had to change the e-prom on a rental chiller, sat outside chiller would trip on low oil temp while chiller was running in cold weather.

[ga1279]

I generally don't like to put a question into a reply but I knew there were some Trane Guru's on site. Doesn't PhaseMe I appreciate the response. Hope I can do the same for you someday.-GEO

[jayguy]

Yes .002 is tight but here is what I'm thinking. If it is not causing any problems with binding the shaft up do you think it will cause any problems associated with oil loss?...

a shaft that is not binding at 4 or 5 rpm is a lot different than a shaft rotating at 3485 rpm when it binds up. a very tight seal is great for preventing oil loss but too tight is also bad.



...I don't it is a non contact seal and if anything it will further minimize any loss compared to excessive clearence. Also it would probably wear in rather quickly too once running and being a lot softer than the shaft I don't think that would pose a problem either...

a soft v-belt will wear out an iron sheave...so a soft metal shaft seal will groove a hard metal shaft...i have seen it and it is not pretty. the really bad part of a seal to shaft contact is that the seal is quite cheap compared to replacing/repairing a shaft. the real problem is if it DOES wear quickly...the metal will 'ball up' and destroy the shaft and seal.

[scott_RWS48]

They come this way now. Just use some scotch bright to make it not rub and your good to go. Remember; it will seal better with a tight fit so don't worry about it.

[acjourneyman]

Overnighted a new seal and it was just as tight, could get .002 in the top but .0015 would only go around to the 10 & 2 point. I ended up using one we had lying around and it was in tolerance, will push the button tomorrow.

[klove]

I've been following this thread to see where it would go. Jay is correct on this one (even if his old avatars were better). That seal is a naturally tight fit due to it's application, but the shaft on that compressor will center under centrifugal force. If you set your seal all the way against the shaft at the bottom so that the total diametral clearance is taken up at the top, then you start dragging every time you shut down, especially as the bearing wears. If you set it .0005 low and have
.0015 at the top, what happens when you start up and the shaft centers while riding on a .002 or so film of oil?

I've hand fit them with the correct tooling for measuring and fitting the seal (labyrinth seal scraper), it's much like scraping a bearing to fit, and done properly is fine. I can't say that I agree with running the seal too tight and "burning" it in ('cause as Jay said, that seal will ruin that shaft), or with arbitrarily resizing it with abrasive material. I do agree with refitting done properly. I've often said that we're not building watches, but this kind of thing is as close as we get.

[stickerhead]

Sand it out a little and it will be fine. That seal I would rather have a little on the tight side to thwart oil loss problems

[Doesn'tPhaseMe]

If you set your seal all the way against the shaft at the bottom so that the total diametral clearance is taken up at the top, then you start dragging every time you shut down, especially as the bearing wears. .

Your suppose to set all the clearence up top at 11:00 and push the seal up against the shaft on the bottom. Thats what is taught in La Crosse and its in the teardown manual too. It can't drag during a shut down because of post lube and there is still a film of oil between the shaft and bearing. The only way is if you loose power.

Since we are only talking about .002 and instead of sanding it how about using a cylinder hone? It is easily obtainable, can be done right on site and will get the same results on all internal surfaces of the seal.

[triggerhappy]

I've been following this thread to see where it would go. Jay is correct on this one (even if his old avatars were better). That seal is a naturally tight fit due to it's application, but the shaft on that compressor will center under centrifugal force. If you set your seal all the way against the shaft at the bottom so that the total diametral clearance is taken up at the top, then you start dragging every time you shut down, especially as the bearing wears. If you set it .0005 low and have
.0015 at the top, what happens when you start up and the shaft centers while riding on a .002 or so film of oil?

I've hand fit them with the correct tooling for measuring and fitting the seal (labyrinth seal scraper), it's much like scraping a bearing to fit, and done properly is fine. I can't say that I agree with running the seal too tight and "burning" it in ('cause as Jay said, that seal will ruin that shaft), or with arbitrarily resizing it with abrasive material. I do agree with refitting done properly. I've often said that we're not building watches, but this kind of thing is as close as we get.

Then would you tell me how you set the lab. seal on the other side of the sleeve brg.

[klove]

Then would you tell me how you set the lab. seal on the other side of the sleeve brg.

Per the overhaul instructions. If I can get to it, I can work with it. If I can't, well, there's not a whole bunch I can do about that. There's things that I'm not very fond of about the way York's are built, either. I certainly didn't mean to imply that the way you do it won't work, and if it offended, you have my apologies. It's simply not the way that I prefer to do it.

I've taken several compressors of different manufacturers apart that have had seal to rotating element contact of various degrees, and it was never pretty. If I can get to it to fit the thing correctly (in my opinion), that's what I do. York had certain things that they "teach" as the correct way, also. I didn't necessarily agree with all of those, either. Sometimes I don't do well with toeing the line just because some college graduate engineer who never set a torque wrench in his life says "Do it this way". I've seen you lean against Trane on occasion, too.

[triggerhappy]

Klove,
Hey no offence taken.
You know me I am just entertaining myself.
I rebuild these machines every day and I find it pretty amusing that people will swallow camels and gag on gnats when it comes to the two seals.
I know that you probably check both seals and replace the oring on the brg. bracket on a brg. inspection but my guess is that most people don't ever know that the other seal is there or just leave it to the motor shop.
Hence my question of how is one seal set in comparison to the other.
By the way the motor shop uses neverseize on the inner lab. much like the old SB calls for on the sidewinders that were binding on rebuild.

[turbomaster]

Just out of curiosity... and I have a method I've used, that works quite well.
How would you set the internal laby seal clearance on a big red double ender?