AC Vacum Pump

[schellmaple]

Has anybody used a vacuum pump used for recharging AC units to put vacuum on their lines? The pump says it has 7CFM. I have a Welch pump now that has 5CFM and I didn’t know if I could add the AC vacuum pump to it if I ever needed more vacuum?

[maple flats]

I don't remember who, but there was a thread about using one this past season. As I recall they loved it. You just need to remember the limitations. #1 is size, while a general rule of thumb is 1 cfm/100 taps, 1 cfm/50 taps is more realistic if you are not on top of fixing every leak every day. #2 is the pump, is it rated to run continuous? Aux. cooling may help, try to set it up with a fan blowing on it to help the cooling, but that may still not be enough.

[MT Pockets Producer]

We used a very small 2.5 cfm Harbor Frieght AC pump on 92 taps with a homemade mechanical releaser and were very pleased. It was a new tubing system so it was leak free and we were able to consistently get readings like the one in the photo. We ended up just shy of double the sap per tap as we had on buckets and that was with some other in-efficiencies such as a too small manifold at the releaser and should have used check valve taps to assist with the vacuum loss when the releaser dumped. As far as the pump heating up, it ran very cool, probably too cool. With a moisture trap and a balance tank we still got a fair amount of moisture in the pump oil as it did not run hot enough to cook it off like the larger pumps might. We would regularly drain the water off until we felt it needed to be changed. Went through just a quart of oil for the season. I wouldn't hesitate to add more taps and probably will. We have three 3/4 inch mains totaling about 450 feet of tubing and the vacuum reeadings at the end of each one was within an inch of what it was at the releaser. Never checked the readings at the end of the laterals. With your pump being a bit larger I am sure you would have as good or better results on a tight system.