Pre-Soak Back Feeding

[Keno]

Hi Group, new problem popped up today, hoping you guys/gals can guide me in the right direction. Noticed that when pre-soak is selected in one of the bays, it is back feeding liquid and air back to the plain water holding tank for the HP soap and wax. Seems like it is only that one bay that is doing it. This is a Mark VII SS setup from about 2005. Any help on where to start trouble shooting would be appreciated.

Thanks,
Keno

 

[MEP001]

That indicates a problem with the bay pump. It should hold back reverse flow. There may be a check valve on the inlet side of the pump, which will also be bad.

 

[Keno]

That indicates a problem with the bay pump. It should hold back reverse flow. There may be a check valve on the inlet side of the pump, which will also be bad.

Thanks for the guidance. Opened up the valves in the CAT 5CP pump and 2 had split o-rings, replaced all the valve o-rings for good measure. 2 valves separated while pulling them out, waiting for the new reversing pliers I ordered to get those out, should be here tomorrow. Will report back once it is all put back together. I didn't see a check valve on the inlet side - but I did see what looks to be a filter, could be a check valve though. Looked something like this https://www.carwashsuperstore.com/Product/677/DEMA-Y-Type-Line-Strainers

 

[MEP001]

It could be a swing check valve, they look very similar, and they don't usually do a good job of preventing backflow. I use these:

Kleen-Rite 944-430 | Brass Inline Check Valve | 1/2in. F x F

This resilient disc check valve is not lead free. It is not for use on potable applications.

www.kleen-ritecorp.com

 

[Keno]

I don't think it is a swing valve as it is mounted vertically. Will check if I see any markings on it tomorrow. All the valves were removed and inspected today. Total of 3 split orings and one valve was completely missing o-ring and backup ring. Broken backup ring was found in the pump o-ring was not found. Backfeeding has stopped after all the valves o-rings were replaced with new. Pressure is much better and pulsations are gone.

 

[Keno]

It could be a swing check valve, they look very similar, and they don't usually do a good job of preventing backflow. I use these:

Kleen-Rite 944-430 | Brass Inline Check Valve | 1/2in. F x F

This resilient disc check valve is not lead free. It is not for use on potable applications.

www.kleen-ritecorp.com

Is a check valve needed in a setup like this Mark VII SS Stand? - water is fed from a holding tank for HP Rinse, HP Soap, and HP Wax

 

[MEP001]

It must not be or you'd have been having lots of problems with tanks overflowing. Mark VII is one SS manufacturer's equipment with which I'm not familiar.

 

[Keno]

I'll try to grab a picture of the valve tomorrow if I can remember