Cat 530 cavitation - any idea what's going on?

[owinborne67]

Got a real head scratcher for y'all - one of my Cat 530's is noisier than the others, and the pressure is inconsistent. Cat tech support said probably cavitation due to an intake or outflow restriction. Today I spent some time going over the piping, re-taping most of the intake, and along the way I noticed what the video shows - when I take off the cold water solenoid and force the pump to run off the backup tank, the cavitation gets a lot better and pressure improves. All of my other pumps are plumbed the same and none have this issue, though this pump is the busiest one.

There's no leaks in the piping on the cold water intake so I'm a little lost what could be causing this - already re-taped most of the joints on that side and replaced the diaphragm in the cold water intake. Figured before I keep tearing it down I should post here in case anyone has any ideas? Thanks!

 

[Blanco]

Busiest one does not matter. You already answered your own question. If the cavitation improves when you supply a new inlet then the issue is with either the solenoid, hose, fittings, possible check valve if you have one, or something else inline on the water feed.

 

[Randy]

Try connecting a hose fed directly with city water pressure and see if the problem gets better. If it goes away or gets better you know you have a water delivery problem.

 

[owinborne67]

Busiest one does not matter. You already answered your own question. If the cavitation improves when you supply a new inlet then the issue is with either the solenoid, hose, fittings, possible check valve if you have one, or something else inline on the water feed.

So that's the weird thing, removing that solenoid closes that inlet (which is city water), not opens it - the valve is spring-loaded, so in my setup (30 year old Ginsan stand) without the solenoid a spring holds it shut, and the pump pulls from the gravity fed water tank. That's why it's confusing, the cavitation gets better when I take the city water away, even though it's at higher pressure. The next pump over is fed from the same city water manifold and it has no issues.

Basically my confusion - is it possible that a line fed with city water, that doesn't leak while the pump is off, could be getting aerated somehow when the pump is on? If so what are the likely explanations for that?

 

[Randy]

It would probably help if you posted some more pictures of the complete system. When kind of valves does this your system use.

 

[owinborne67]

Attached an old pic of the entire system, don't think that adds much context though unless some of you know this pump stand setup - basic overview of the water feed system, hopefully it helps!:

• Central tank contains three tanks
  • HP soap mixer
  • HP wax mixer
  • gravity feed water tank - this is connected to all pumps by water lines that feed by gravity
• Each pump is also fed with cold city water at 60 psi by manifolds built into the pump stand
• Pre-mixed HP soap is drawn into the pumps directly - when HP soap is engaged, the solenoid in the earlier video turns off and closes off the cold water (central tank water is hot)
• If the solenoid fails, each pump can still draw water from the gravity feed so it doesn't run dry
• Pre-mixed HP wax is pumped into the cold water feed via an injector (HP wax is shut off by solenoid when not selected)
• 

 

[Blanco]

It's common for manufactures to have a cold water rinse solenoid. They do that to clear the lines of HPS, Wax, and etc faster when switching to high pressure rinse. Usually there is a check valve on the bottom of a gravity feed rinse tank. I would make sure that check valve is working properly.

Removing a solenoid will never close an inlet. Your must be talking about just the coil that energizes the solenoid and not the solenoid it self. Yes if you remove the coil the solenoid will be NC (normally closed) and will not allow water to pass through.