Cat pump 310 issue? when using Spot Free

[howiez]

Hi all, new here.

One of my pump is working fine with consistent and stable at high pressure rinse. But when switch to Spot free for low pressure, pressure gauge is jumping from 100 psi to 500 psi, and loud vibration sound can be heard through out flow line to the bay.
I checked seals for both high and low pressure, they looked in decent conditions. Also ensured oil level inside the pump.
Anybody would recommend where I can trouble shoot this problem?

Thanks in advance.

 

[MEP001]

So the spot-free runs through the same pump as the high pressure? If so, I would have to guess the spot-free regulator is bad.

 

[howiez]

Thank you very much. Yes it was the solenoid valve gone that controls spot free that has gone bad. Problem solved now