Vacuum pump maitenance


I’m setting up second hand casting equipment, specificly a vacuum
caster (Vigor, hardly used but not young), I can’t find documentation
on it for love nor money. Anyway, this lovely piece of possible
palentology doesn’t seem to have much oomph to it. Past the seals,
what should I be looking for/checking? Most directly, how much oil
should be in the machine? All I’ve found on the subject is warnings
not to over fill, and as I can’t see an indicator I’m a mite
bafffled; and thoroughly loath to just drain 'er and pour more in


Based on my experiences with using a vacum pump for dehydration of
refrigerant systems; I would reccomend the following: Use only vacum
pump oil. A rep for J/B told me a pump with worn seals can sometimes
be reconditioned by running the pump with the lines shut off, fresh
oil, and run for a day or more continously. Then drain the oil while
hot and plug the exhaust with your hand while on and draining. This
will help to push the crud out of the bottem of the pump. The seals
many times will wear in and seal again. The air ballast valve is
used to help purge the pump; I valve off the vacum lines and open the
ballast valve and leave the pump run while I do other things; to help
keep the oil clean. Some wear items are the coupling between the
motor and the pump, o rings on the ballast valve, possibly a belt
etc. The most common vacum pumps are probably those used in the air
conditioning / refrigeration trade. Ritchie, J/B, and Thermal are 3
common brand names; Welch is a common scientific brand. Most pumps
have a sight glass; fill it to the 1/2 way or slightly more point. If
the oil looks “milky” it is contaminated with water and should be
changed. Use the largest practical diameter piping for your vacum
lines, keeping them as short and straight as practical. Use special
hoses or copper tubing, or regular pipe. Please notice that if you
look at refrigerant hoses some are rated for vacum and others not
specifically, they will not work as well for a vacum and can collapse

Look at pictures in a catalog (Grainger’s etc.) or go to a
refrigeration wholesaler in person. I bet that the pump you have is
made by someone other than Vigor. You may see similar pumps.
Overfilling with oil has just resulted in the excess oil spitting out
the exhaust, at least on the styles I am familiar with. I hope this
all helps. e-mail me off list if you have further questions.

Dan Wellman