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kold Keeper
19-11-2013, 04:30 AM
The shaft seal was replaced 1.5 years ago because of a NH3 leak.

It was replaced again 8 months ago because of excess oil leaking.

Its leaking a liter to a liter and a half a day of oil.

Any advice? I wasnt involved in either of the previous replacements so i cant rule out human error either.

Im about to order another shaft seal but I want to check around first.

Thanks for any advice!!:D

Segei
19-11-2013, 06:19 AM
Alignment hot and cold.

RANGER1
19-11-2013, 09:24 PM
As Segei suggests, get laser alignment checking for "soft foot" as well.
grasso recommend thrust bearing check every 5000 hours as well (pretty simple especially if you change seal at the same time).
If using synthetic oil HNBR "0" rings in seal are more suited against "0" ring shrinkage (neoprene).

How many hours on this compressor, has it had a major service. I would suggest 20-30 000 hrs.

Also helpful to know condition of seal faces & "0" rings in old seals.
Oil filters changed regularly
oil temp
running conditions

kold Keeper
19-11-2013, 11:46 PM
The motor was recently replaced. It shorted out. They said it was overloaded. A GEA tech came and did a cold and hot alignment. He aslo checked the thrust bearings. But im pretty sure he did a dial indicator alignment. The work report says 0.00015 of end play in male rotor and the shaft seal is leaking oil at a rate of 48 dpm on the report.

gonna get hold of him tomorrow to see if he noticed any soft foot.

The leak actually slows down intermittently and then pours it out again for a week, then slows down for a few days.

Using mineral oil. should we be using the HNBR o-rings? we use the ones in the kit always.

23,744 run hours. no other major compressor work done.

filters should be being changed.

3# oil filter diff.

116 deg. inlet oil temp--steady on trend graph

189# oil filter inlet pressure

183# inlet oil pressure

135# Discharge pressure

156 deg. discharge temp

136 deg oil seperator temp.

48# oil differential

26# suction pressure

Thanks for the help!

Segei
20-11-2013, 04:30 PM
Sometimes low oil temperature can be issue. Try to increase oil temperature to 130F. Do you have liquid injection oil cooling?

kold Keeper
20-11-2013, 10:15 PM
the oil is cooled by cooling water.

RANGER1
20-11-2013, 10:19 PM
The motor was recently replaced. It shorted out. They said it was overloaded. A GEA tech came and did a cold and hot alignment. He aslo checked the thrust bearings. But im pretty sure he did a dial indicator alignment. The work report says 0.00015 of end play in male rotor and the shaft seal is leaking oil at a rate of 48 dpm on the report.

gonna get hold of him tomorrow to see if he noticed any soft foot.

The leak actually slows down intermittently and then pours it out again for a week, then slows down for a few days.

Using mineral oil. should we be using the HNBR o-rings? we use the ones in the kit always.

23,744 run hours. no other major compressor work done.

filters should be being changed.

3# oil filter diff.

116 deg. inlet oil temp--steady on trend graph

189# oil filter inlet pressure

183# inlet oil pressure

135# Discharge pressure

156 deg. discharge temp

136 deg oil seperator temp.

48# oil differential

26# suction pressure

Thanks for the help!


I'm a bit concerned with the oil pressure, as maximum is 350 kpa or 51 psi nett oil differential pressure.

If it gets above it, there is a possibility of male rotor driving towards or driving into discharge end housing.

I would set oil pressure to approx (depending on oil pressure trip point) 30-42 psi differential.

OK GEA has just carried out thrust check, so I assume he checked both rotors discharge end clearance, not
just thrust bearing end play as you posted.
If male rotor did move because of oil pressure, I thought it was a possibility.

Grasso have design floor (they probably refer to it as a characteristic or limit), if oil pressure to high it drives male rotor balance piston into discharge end housing, as it overcomes thrust bearing outer race spring force.
Hopefully this has not happened & should be picked up during thrust check.
If it was happening it may disturb seal faces, also even carrying out discharge end clearance check may disturb it as well.

Neoprene "0" rings OK for mineral oil, who knows which ones they supply in kit, as long as you are aware.
Need to know what old seal condition when it is removed.

I also suggest overhaul may need to be carried out in next 12 months if possible, would be interesting what GEA recommend.
They recommend thrust check every 5000 hrs.

Oil analysis could also be helpful if oil in poor condition.

kold Keeper
26-11-2013, 01:43 AM
Lowered the oil pressure to 30# on both compressors that are leaking oil "on and off."

Where are you referencing the Grasso design floor of 51 psi nett oil differential pressure from?

On our compressor "log" sheets the company recently added a "normal range" key. It says nett oil pressure is good between 20-60 psi.

RANGER1
26-11-2013, 11:59 AM
Cold keeper,
Can you give us compressor nameplate details so I can pass on accurate information.
When I look up GL it shows LT series or large series.

Lets not refer to it as design floor as thats my opinion, lets call it maximum oil pressure or limitation.

kold Keeper
27-11-2013, 12:26 AM
The nameplate is M#: YR-Y2655S, Mark: 7, Year: 2008.
Data Sticker inside door is M#: 565GL, Year: 2009

The other compressor nameplate with same problem is M#: XB-1, Mark: 4, Year: 2005
Data Sticker inside door is M#: 1025TGLB, Year: 2005

kold Keeper
21-01-2014, 12:52 AM
Update:

both compressors have stopped leaking mass quantities of oil.

Lowered the high stage to 30# oil diff.

Lowered the booster to 25# oil diff.

RANGER1
21-01-2014, 07:59 PM
Update:

both compressors have stopped leaking mass quantities of oil.

Lowered the high stage to 30# oil diff.

Lowered the booster to 25# oil diff.


Thanks for update.

Josip
21-01-2014, 08:38 PM
Hi, all :)


Update:

both compressors have stopped leaking mass quantities of oil.

Lowered the high stage to 30# oil diff.

Lowered the booster to 25# oil diff.

Thanks for update ...

Again confirmed, (please give us all available information ... what we always ask OP) sometimes is very important to have as much as possible plant/compressor data like refrigerant/oil/cooling water/secondary refrigerant or air temperature/pressure/flow to be able to make a good troubleshooting and suggest what is possible to do.

Lesson learned.

Best regards, Josip :)