Thread: Shop air A/C Vacuum pumps

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How well do these type of A/C vacuum pumps work? How much compressor air do they consume? I have a very occasional need to evacuate an A/C system and wonder if one of these would meet my needs versus a motor driven pump. I have a mid sized shop compressor with a 60 gallon tank.

http://www.ctd4ac.com/pdf/22-1600%20instructions.pdf

thanks

Pat

A friend of main made one outta a refrig. compressor & it'll pull down a sealed system down to almost ZERO in just a matter of minutes. the only cost he truly had was the fitting he had to use to hook up the gauges up to it...joe

Originally Posted by Stu Cool

How well do these type of A/C vacuum pumps work? How much compressor air do they consume? I have a very occasional need to evacuate an A/C system and wonder if one of these would meet my needs versus a motor driven pump. I have a mid sized shop compressor with a 60 gallon tank.

http://www.ctd4ac.com/pdf/22-1600%20instructions.pdf

thanksPat

they use a lot of air and not correct for evacuating an ac system best bet is maybe buy an inexspensive vacuum pump from Harbor freight. or you can make one from a rotory compressor from a refrig. old GE compressors. I put one asside years ago.ED

Stu, as mentioned they use a ton of air and are aggravatingly noisy,( especially as you need to pull the system down for at least 20 minuets) and the air pressure drops so does the amount of vacuum you are pulling.

That being said they do work “well enough” and your compressor will probably be enough.

Inches of Mercury Boiling Point of Water °F
26.45 120
27.32 110
27.99 100
28.50 90
28.89 80
29.18 70
29.40 60
29.66 50
29.71 40
29.76 30
29.82 20
29.86 10
All values are at sea level. Subtract 1 inch for each 1000 ft. above sea level

If the venturi pump can pull 28.3 inches, the temperature would have to be at least 72 degrees...so far, so good. However, the venturi pump is not very fast....like Mike said, you have to leave it pulling on the system for at least 20-30 minutes AFTER it reaches the vacuum level corresponding to the temp. If a system has been open very long, I usually pump for more than an hour....quite a chore for a venturi pump. Of course, here in Southern Arizona, we have no humidity so there is no need to evacuate.

Thanks everyone, I think I will hold out till I can get a good one, or rent one from the local United Rents on the rare occasion I need one. I am watching Craig's list and Ebay now. I am not in a rush as it is not exactly AC season

Pat

It looks like there are several on ebay for $50-75.

Imperative for these pumps to have the oil changed frequently.
Some even recommend changing weekly if they are being
used.

Yeah I have a bid in on one of them now. Ends in a couple hours, If I don't get it for the price I want, I'll bid on the next one.

Thanks

Pat

have wanted a vacuum pump myself
but one from an old freezer would need to be
evacuated before you could remove it
without releasing bad things to the atmosphere

Looky what I got! And it's a quality Snap on Piece too:

http://cgi.ebay.com/ebaymotors/ws/eB...SA:MOTORS:1123

Pat