Hello, about the gas pump for a long time, (paint) water problems. You say that the air pump under the water FA open, refers to the water separation?
Waterproof valve is a valve under the gas tank, is used to drain water and oil impurities. If your spraying process is not very strict, you can use an air pump + spray gun.If the spray process requirements are more stringent, you need to configure the initial filter, fine filtration and high pressure air cold dry (dehumidification), better.
This "drain valve" means the valve under the belly of the air pump. You bend over and have a look at it. Turn it off with the vise.
The best air pump will always have this kind of thing! I changed a few times as the water! Then, add a gas tank, just fine! But things are pretty much the same! The only double or 3 lots of heavy water! To solve the problem!
