Thread: Boxxer 427 Chem Pump Seems to Loose Prime

What don't I know about the chem pump on my Boxxer 427? It seems to loose the prime, even between jobs. There have been times I've used my rinse, turned off the chem pump to prespray another area, and then need to prime again.

I just tried cleaning the chem system with vinegar per the Boxxer manual - place hose in a jug of vinegar, run it through wand at 10gph, then flush with water. I was running through an Evolution wand but could not get gph above 3. Even using an open end hose it would only go to 6.

Does this make sense? Thanks in advance for your thoughts.

I'm pretty sure it must be the same pump they put on the Boxxer 421. Mine has never really worked much better than what you are describing. Fortunately I almost always use either the 2 or 3 gph setting anyway so it really hasn't been an issue. I don't think mine will go much higher than six no matter what unless it is being primed with my hand over the vacuum slot. Even at 3 gph you will go through that 5 gallon container pretty quick. If it's working and you can at least set it between 2 to 4 gph I personally wouldn't worry about it. I can tell you that I'm pretty sure even replacing the diaphragm, o-rings, and two check valves will not improve it. At least it did not improve mine as far as getting any higher gph. It is fairly simple to rebuild if you continue to have problems that is really your only option.

You should not have to reprime it every time between jobs though. That could indicate either an air leak or a weak diaphragm I would think. I may have to put the above mentioned parts in mine pretty soon. Jondon sells the replacement parts if you want to try and rebuild it yourself. Fortunately those parts are fairly inexpensive. The biggest hassle is just doing it.