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Welch Vacuum Pump

MikeC5 on Fri July 31, 2009 9:34 PM User is offlineView users profile

Year: ?
Make: Welch
Model: 1400
Country of Origin: United States

I was given a vacuum pump a few years ago and it seems to work well. A Welch Model 1400 which is a vane-type pump. The specs say it moves 1.0 cfm and can get to 0.13 microns (if I did the conversion right from 10 to the minus 4 torr). It was used with a small vacuum chamber (maybe 1/2 to 3/4 cubic foot volume) and seems like it would work for auto AC. Is 1.0 cfm sufficient or will it take ages to get to low levels of vacuum?

Cussboy on Sat August 01, 2009 11:09 AM User is offline

I'd say use it. I use a laboratory style vacuum pump on my stuff, have a thick rubber hose coming off it hose clamped to a hose barb and 1/4 flare fitting, which goes to my gauge set. The gauge set has hose adapter lines to fit R134a. The goal with a vacuum pump is to pull out essentially all of the air, and to lower the pressure (vacuum) inside the system so any moisture will boil off. Lower pressures mean that moisture will boil off at ambient temperatures. So even if your gauge shows 29 psi vacuum instead of 30 psi, you could just pull vacuum for longer time.

I never even tried to do away with the rubber hose on my set-up, didn't see any value to try, personally.

zzljg on Sat August 01, 2009 9:08 PM User is offline

It's a great little pump,,,very familar with it,,,,should do auto a/c as long as it tests out ok to pull good vacuum,,,


MikeC5 on Tue August 04, 2009 7:22 PM User is offlineView users profile

Thanks very much guys. I'll let you know how it goes.

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