Oil leak on small a/c vacuum pump

[DaveB]

This year I'm using a small A/C style vacuum pump and a dairy releaser for a small 60 tap setup that I have. I know other folks have used this pumps before from Harbor Freight (http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html) so I ordered a similar one (https://www.amazon.com/Zeny-Single-Stage-Economy-Conditioner-Refrigerant/dp/B012CFTYX4/) from Amazon. The pump worked fine the first day but when I turned it the second day I noticed that it had leaked oil out of the fill/vent port and that there was very little oil left in the reservoir.

The pump works fine and I expected a little oil to come out of the exhaust (to the tune of a quart over the whole season) but I didn't expect most of the reservoir to be drained. The port cap was a little loose when I checked that and I'm wondering if I just need to check that daily before starting it.

For guys that use these pumps, is it common for the cap to loosen or lose that much oil? I'm going to attach a hose to the vent so that I might be able to re-capture some of that oil but I just don't know what else to expect from using these types of pumps.

[MT Pockets Producer]

1559915600

The exhaust port cap on our HF pump is a two piece affair and the cap sets on top of the threaded part and slides up and down in a loose fashion to allow the exhaust to escape. We had the same issue with losing oil. We fixed it by removing the sliding portion of the cap, leaving the little diaphragm in place and putting a rubber tube over the entire fitting and clamping it in place with a hose clamp. Push it down tight against the pump body and it seals it pretty well and keeps the oil in the pump. We actually used the top portion of a washing machine drain hose that would hook into your household drain. It was the proper diameter and allowed us to put a barbed hose fitting in the other end to connect to a piece of one inch pipe. We then put the end of a pipe in a jug and catch any mist or residue that comes out. This pump is no Gast or any of the other well known brands but this is season three with it and is still pulling 26 -27". Not bad considering the amount of moister, ice and lack of oil it has endured from time to time.

[DaveB]

That helps me. My pump has a slightly different port but I'm planning on clamping a hose to it and run it so I can capture some of the run off.

Thanks again for the pictures!