Cat Pump Help

[SparklesSS]

Hi all,

I have a Custom Craft setup that has been great with the exception of 1 bay. I have 1 bay that keeps acting up. The previous owner struggled with this bay for almost 3 years. Here it is:

Took over the wash a little over a month ago. Cat 5CP2120W started knocking a bit in the last week. Started getting worse to the point where the high pressure functions would not go past 900 psi and the pressure would fluctuate up and down with bad knock. Low pressure seemed to be fine. Walked into the pump room a few days back and when the weep would kick on the pump seals would drip water. I pulled the pump head and rebuilt it. I also took the solenoid valves off the block to see if there was any water obstruction and changed a check valve just to be safe.

Pump seems to be working fine now but the previous owner indicated he would rebuild the pump and it would work well for him for about 1-2 weeks before it would start acting up again. He has even changed to a new head in the last year and it lasted a bit but then started cavitating again.

Any idea what could be causing this? Is it lack of water flow?

Other 3 bays seem to be working fine with no issues.

 

[I.B. Washincars]

It sounds like you have a cavitation issue. It's probably washing out head. That would explain why it works for a bit and starts doing the same thing again. Is/was the head washed out, or was he just blindly throwing new parts at it.

 

[SparklesSS]

It sounds like you have a cavitation issue. It's probably washing out head. That would explain why it works for a bit and starts doing the same thing again. Is/was the head washed out, or was he just blindly throwing new parts at it.

He told me he rebuilt it a few times and then proceeded to replace the head. When I rebuilt the head I looked for signs of washout and could not see any visible pitting or indentation around the ring seats but I am new to this.

 

[MEP001]

One of the plungers could be misaligned and wearing the low pressure seals prematurely, then it would start sucking air in through the bad seal or, as you've already seen, leaking from the seal when the weep is on.

 

[SparklesSS]

One of the plungers could be misaligned and wearing the low pressure seals prematurely, then it would start sucking air in through the bad seal or, as you've already seen, leaking from the seal when the weep is on.

Thanks. I did remove the plungers to inspect them during the rebuild so hopefully they are better aligned.

 

[mjwalsh]

Is that the type of system that VFD runs lower pressure options thru the Cat Pumps via programmed RPM change?

 

[SparklesSS]

Is that the type of system that VFD runs lower pressure options thru the Cat Pumps via programmed RPM change?

No has two solenoid valves that open below the pump for low pressure

 

[MEP001]

Is that the type of system that VFD runs lower pressure options thru the Cat Pumps via programmed RPM change?

What difference would that make if it were the case?

 

[SparklesSS]

What difference would that make if it were the case?

Called the previous owner and he indicated he changes the seals every 3 months as regular maintenance. It is a busy wash but does this seem normal to you?

 

[MEP001]

That's not normal. My busiest bays get 1500 hours a year and I don't change the seals every year.

 

[I.B. Washincars]

Called the previous owner and he indicated he changes the seals every 3 months as regular maintenance. It is a busy wash but does this seem normal to you?

No, that's insane.

 

[Randy]

The Cat 5CP pump is known to having head wash out issues. Probably the best thing you could do is replace the pump with an Cat 310 or Arimitsu 313. You might want to check your incoming water supply, you could be straving the pump or pulling in air somewhere. It's not normall to change seals every 3 months.