Help with cavitation after replacing seals and valves.

[Thisguyswash]

Hey everyone. I am a relatively new owner of a two bay self service wash and am having an issue with cavitation. My bays use belt driven Cat 5CP2120W pumps and today I replaced the high and low pressure seals and all 6 valves. However, there is a slight cavitation when spraying at full pressure. I did the same work to my other bay it it sprays rock solid.

Any suggestions for things to check?

Here is a picture of my configuration.

 

[Greg Pack]

Check for adequate inlet water flow. Look for any water leak on the suction side. Also, look for anywhere a small amount of air could be getting in the water stream. Anywhere water is leaking out air can get in when the pump is running. If all that is OK, I'd swap with another bay unloader.

 

[Thisguyswash]

Check for adequate inlet water flow. Look for any water leak on the suction side. Also, look for anywhere a small amount of air could be getting in the water stream. Anywhere water is leaking out air can get in when the pump is running. If all that is OK, I'd swap with another bay unloader.

Thanks.
I did notice that there is a slow drip from the adjustment screw on the soap solenoid. Could that cause this?

 

[Yeti55]

I just had a similar issue with one of mine , the check valve on the water inlet had something in it . Pulled it out and good as new

 

[Greg Pack]

Thanks.
I did notice that there is a slow drip from the adjustment screw on the soap solenoid. Could that cause this?

Maybe? I guess if it is downstream of the valve that shuts off soap flow itself it's a possibility. It's worth investigation

 

[OurTown]

Do you have hot water gravity feed soap and wax with a cold city pressure rinse? If so does it pulsate on all three functions?

 

[Thisguyswash]

The soap and wax are each pulled in via suction after being mixed with a hydrominder. The mixing happens in buckets on the floor, so below the pumps. But yes it happens on all three settings. Here is a picture of the layout.

 

[Randy]

Did you happen to inspect the head for head "wash out"? The 5CP pump head is known to wash out. That's the first place I'd start looking.

 

[Thisguyswash]

I am not familiar with "wash out". Can you explain?

Thanks.

 

[Greg Pack]

How do your cat pumps get water? Is it pressure fed, or is there a tank outside the picture that feeds via gravity?

 

[Thisguyswash]

How do your cat pumps get water? Is it pressure fed, or is there a tank outside the picture that feeds via gravity?

There is a tank below each pump that is fed by the hot and cold lines. The tank then goes to a ball valve and connects to a check valve. On the other end of that there is a hosethat goes directly vertical to the inlet of the pump. I'm going to inspect the check valve this afternoon and see if there is an obstruction in it.

 

[2Biz]

I am not familiar with "wash out". Can you explain?

Thanks.

Lots of good information about Wash Out in the thread "Link" below. It used to be a "Sticky" Thread, always visible at the top of the self serve threads....Don't know why its not there any more?

(31) Washed out 310 manifolds - With pictures | Car Wash Forum

 

[SudsMaster]

I'm a bit confused. What does "wash out" mean? Could anyone explain it to me?

 

[HeyVern]

I'm a bit confused. What does "wash out" mean? Could anyone explain it to me?

check the thread in the previous post.

 

[2Biz]

I'm a bit confused. What does "wash out" mean? Could anyone explain it to me?

Wash Out is what happens when the seals wear out and allow water to errode the metal in the head around the seals. Once this happens, new seals won't fix cavitation. The head will need to be repaired. The thread that I linked to above walks you through every step of this issue with pictures of what washout looks like.

 

[Thisguyswash]

So I got it fixed tonight and it was the leaking soap solenoid! Hard to believe that such a small leak could cause all that. I guess on the bright side I have a new dumper, check valves, and solenoid. Plus a new set of valves and seals. Ugh. Just glad it's working again. Thanks everyone for all the help and especially Greg Pack for the info about leaks in the inlet side.

 

[Thisguyswash]

Lots of good information about Wash Out in the thread "Link" below. It used to be a "Sticky" Thread, always visible at the top of the self serve threads....Don't know why its not there any more?

(31) Washed out 310 manifolds - With pictures | Car Wash Forum

Thanks for the link. I was able to review the pics and compare to my valve seats which do not appear to be affected by wash out. I will keep that in mind when replacing seals though.