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View Full Version : The Oil Sight Glass Shows a low Oil Level!



Grizzly
05-08-2008, 05:31 PM
As the thread title suggests.
When there is a low oil level in the sight glass, does it always mean that the compressor is short of Oil?
NO!
Most of the guys on this forum will already know this.
Basically most recips when running at Low Loads for long periods.
Will have a higher than normal rate of "oil carry over"
resulting in sometimes the compressor tripping on oil failure.
The older and more tired the machine the more this can happen.
So as a tip from an old timer!
Next time you see a comp with low oil level and provided there is enough oil left in it to do so?
Run the compressor for long enough to allow it to fully load up.
This will force the oil that has been sitting out in the system to return to the compressor sump.
It may require running for a fair while but you will be amazed at the amount of oil that will come back.
Also the set point may have to be dropped to induce enough load.
Of course there could be many other reasons why the oil level is low.
But I seem to be finding a lot lately with the above problem.
Cheers Steve.

NoNickName
05-08-2008, 06:24 PM
God bless you. Please spread the Word. Us compressor manufacturers will thank and bless you.

chemi-cool
05-08-2008, 06:59 PM
Good and true one Grizzly!

The Viking
05-08-2008, 07:16 PM
True, so true.

Simple words of wisdom that are so often forgotten.

A couple of years ago I was called in to look at a chiller that didn't work, another engineer had already spent over a week on it.

When I arrived the valve plates were all smashed up, the story from the first engineer went something like:
-Called in, found OP switch tripped. No oil in sight-glass added 5 l (!!!)
-Got compressor running but found the circuit SOG. Pressure tested, repaired leak and re-commissioned the unit.

I got called in the day after and the oil I managed to get out of the system were over twice the volume the manufacturer recommended!

1torr
05-08-2008, 07:23 PM
Hi Steve. J type? Been there so many times.

Grizzly
05-08-2008, 09:21 PM
Hi Steve. J type? Been there so many times.

Yep J type are bad but they are not alone as NoNickName points out.
Unless they are now made in Italy!
Out of interest N.N.N. Have you any particular elegance to a specific Manufacturer?
Curious that's all.
I can think of quite a few good recip companies
Who have Italian Roots.
Steve.

NoNickName
05-08-2008, 09:33 PM
Frascold, my present employer

Grizzly
05-08-2008, 09:35 PM
Frascold, my present employer

Impressive.
logged and remebered.
Steve