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bernard
02-09-2004, 08:19 PM
With ref to packs is it possible to have an oil leak but not a gas leak.

bernard

Peter_1
02-09-2004, 08:50 PM
The is pushed out of the system by the gas pressure, so if you have an oil leak, you have also a gas leak, bu tit can be a small one.

Latte
02-09-2004, 09:57 PM
Hi Bernard,

Well in theory, if you have lost some oil then common sense would make you think that gas has escaped as well.

Now the but,

For those on the mobile forum will tell you, compressor shaft seals are very common to leak and you don't loose gas when they go. In fact Thermo King (probably the second largest reefer company in the world) will tell you that a certain amount of oil leakage is OK. I don't know that that works, perhaps Reeferjon or MRW have a memo giving the official explanation

At the end of the day, if it is a site you go to a lot, clean/wash/paint the pack, any new sign of oil therefore can alart you to a possible leak. All the supermarket guys will tell you if the plantroom is spotless it make leak detection easier.


Speaking of leak detection, does anybody routenely put UV dye into systems as a matter of course or just when you have continious leaks.


regards

Raymond

Mark
04-09-2004, 05:08 PM
Hi bernard :)

Personally i agree with peter,oil leaks = refrigerant loss and should allways be repaired accordingly :)

Best regards Mark

Andy
05-09-2004, 10:19 AM
Hi :)
it is possible to have an oil leak without refrigerant, or minimal refrigerant leakage.
I know of one supermarket pack, on R22 that required oil top ups once a month, but lost virtually no gas. The underside of a suction line (mains) as it droped into the floor ducts was leaking, pushing the oil into the floor ducts, but losing in general terms no measurable amount of refrigerant.
The suction line was repaired, no gas was added at this point, and the oil usage stopped.
Kind Regards. Andy. :)
That would however be an extreme case :D

bernard
05-09-2004, 10:46 AM
Hi andy how much gas would you expect to loose from a shaft seal.I have one which is looseing oil but no gas or nothing you would notice.

regards bernard

Andy
05-09-2004, 11:19 AM
Hi Bernard :)
oil leakage from a shaft seal is normal and essential to stop the sealing faces burning. Excessive oil leakage can be determined by a sudden increase from the normal. Amounts of oil leaked are very hard to quantify, ie what is normal. Better looking out from a sharp increase in usage.
Oil leakage from a shaft seal may indicate a problem with the shaft seal (wear or debri) or indicate that the crankshaft thrust is excessive. Alway check and compare the thurst clearance (machinine degased) against the manufactures limits. A shaft sel that leaks oil during the running, but even with worn thrust bearings may not leak refrigerant whilst running. Off cycle the compressor for say one hour then leak test (with gas pressure in the crankcase), this will better tell you the condition of the seal.
P.S when checking the thrust, rotate the crankshat and measure at four differing crankshaft positions, this will indicate wear better.

KInd Regards, Andy :)

Mark
05-09-2004, 05:43 PM
Yes,quite Andy. Maybe an exaggeration of mine to make a point if talking about EVERY oil leak :)
I was referring more to the ominous oil leaks that can be overlooked sometimes ,and snowball into bigger problems. :(

chemi-cool
05-09-2004, 06:01 PM
Accept from shaft oil leaks which essential for the seal.
All oil leaks should be treated as refrigerant leaks.

inside the system, oil is mixed with refrigerant and if the system is a 404 one then it is very important to avoid any leak as the refrigerant will loose vapour which will change the refrigerant characteristic.

Chemi