"Tim Wescott" wrote in message
news
anorton wrote:

wrote in message
...
I purchased a used Robinair 15102-A vac pump last winter (much better
price off season). Now I am ready to use it. I added oil (did not
replace the old oil since I was doing a test evacuation) and hooked
the vac pump up to the vehicle's A/C system. I was able to pull 26 or
27 in of Hg of vacum. As I understand it I will need to pull 29 in of
Hg to properly evacuate the A/C system (after repair).

Will changing the oil have an effect on the pump's performance (pull a
stronger vacuum)? I searched for a manual or an exploded view of the
pump with no success. What other sort of maintanence might I need to
do to the pump? Other than hooking the pump up and letting it run,
are there any other proceedures that I should / need to follow?
Suggestions / links to info very much appreciated.

I do not know much about A/C systems or vacuum pump repair, but I do know
that you can not pull more than the local atmospheric pressure which
changes with altitutde and weather. For example, in Denver it averages
24.8 mm Hg.

True. You'd almost want an absolute pressure meter (i.e. one that reads
24.8 mm Hg in Denver, and 0 in a perfect vacuum) rather than a relative
one.

Or be ready to adjust for altitude...

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com

Oops, my goof. That should be 24.8 in. Hg in Denver.