Anyone who uses a plastic tank to bring water to their customers in the Mobile Detailing Industry subsector knows that if air gets into the line between the tank and pump the pressure washer will not work. There is no time to waste when dealing with an airlock problem. Why does this happen?
You must understand that different pumps work a little differently. The engine generally is not the issue, rather the pump. Centripetal pumps usually do not such the water well from a tank. Diaphragm pumps do. Pumps like General or CAT or the look-a-like units suck from a tank okay, but it is better to prime them. They say CAT pumps have nine lives, so if you are only sucking air for a while, you will most likely not "burn it up" but on a General Type or knock-off pump you can ruin it and the porcelain pistons can crack, not good.
I recommend taking the hose that goes from the tank to the pressure washer off at the pressure washer side – then lowering it below the pump and turning the pump on. While water is flowing out by gravity, plug it or screw the hose threads back into the pressure washer or onto the hose barb. If it has a clamp on it, then tighten the clamp. This will insure the system is primed with water.
Make sure the connection is tight and no water is leaking out, as this means air can also get in, especially if the plastic tank outlet is lower than the height of the pressure washer inlet. Also, remember this procedure if you run the tank out of water. The tank should be not lower than the inlet for the pump or you will continually have these problems.
In addition, when you drive the truck the water tank in the back or on a trailer swishes and air can get into the line and make your life difficult when you go to use the pressure washer. Remember, since some pumps, suck well from tanks and others do not, the best policy is to put the tank as low as possible, this also helps with your weight distribution for safety.
If you are a Mobile Car Washer or Own a mobile auto detailing company; I would invite you to read my articles online:
www.EzineArticles.com
At the top center of the home page is a search feature so type in;
1.) "mobile car wash"
2.) "mobile detailing"
There are about 250 articles there for you to read. Sincerely, Lance.