Issue when customer starts with HP soap or Presoak - Pump makes a racket!

[Car_Wash_Guy]

I've been having a issue with some CAT 5CP2120W pumps on my SS side.

When a customer comes in, they'll insert their money, appears to gran the gun while pulling in the trigger, and then selecting either HP soap or Pre Soak.

Once they do that, and the pump begins to run, it struggles to build up pressure. Some times it goes to 200psi-shoots to 600psi- falls back down to 200- then eventually making it's way to normal. While it's doing this, it's making an absolute racket!

This is my first wash, and I'm totally virgin at troubleshooting. I've checked for leaks. I've ensured that the chemicals are reaching the manifold.

Any help would be greatly appreciated!

 

[wash4me]

Probably a restriction and or sit in the suction line. To test this theory feed the pump from a temporary tank with no check valves etc above the pump.

 

[cantbreak80]

Remove the pump's soap inlet fitting and replace it with a plug. Run the pump. If the issue is resolved, you've got an air leak in the soap supply. Air leaks are sneaky...they don't always drip.

 

[getnbusy]

I agree that is sounds to be an air leak on the incoming side. COuld be at the wax line, soap line, water line elbo, inlet filter, loose clamp etc etc