Randy said:
There is a WIDE range in price between the venturi style,
air-compressor powered A/C vac pumps and the electric powered ones
(like $30 compared to $150). Does anyone here have any experience
using one of the "economy" venturi pumps with success? I don't mind
buying good tools, but it would be nice to be able to save some $$ on
one like this which will get very limited use.
__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"
The venturi type are not really very good.
If you're comfortable lashing something together, this place
https://surpluscityliquidators.com/ usually has a selection of new
surplus rotary compressors designed for window AC units. I paid less
than 10 bucks for mine and another $2 for the capacitor it needed. I
soldered a refrigeration fitting onto the inlet pipe and connect my
manifold to that. Once it's all hooked up, I set it in a bucket with
about 3" of water (well below the electrical terminals!) to keep it cool
as there's no refrigerant flowing through it, then fire it up and let it
run for about a half hour to pull a nice tight vacuum. It works very
well, much better than even real vacuum pumps of the diaphragm type.
Yeah, it's ghetto, but I've used it to service probably a dozen
automotive AC systems and install several residential heat pump/AC units.
You also could look on ebay, a couple years ago I picked up a nice
(well, hideous when I got it) Welch Duo-Seal 2 stage vacuum pump for a
buck. It looked like it had been dredged from the bottom of a lake, but
a thorough cleaning, coat of paint, new oil seal and intake gasket,
followed by a couple of days of running flushing oil and then a fresh
oil change had it pumping down to under 2 microns. A new pump of that
ability is pushing up on $2K. Even the most tired worn out abused rotary
vane vacuum pump will work better than an air powered venturi. Heck, a
modified bicycle tire pump probably would too.
