HP pump lost prime?

[Eric H]

I was working at the wash today when a customer came up to me to complain that on of my bays was not working. The LP functions were fine but there was no HP. I went into the equipment room and the pump was running but reading zero on the pressure gauge and no water at the wand. I turned the bay off, took off the hose going to the bay, pushed in the motor starter to start the pump and water came out of the pump. I then put the hose back on and the bay ran fine for the following 2 customers.
What is going on here?
It certainally is not and electrical problem. the pump motor was running.
Possibly an air pocket? but how? What do I need to do to prevent this in the future?

 

[MEP001]

Is your tire cleaner and/or presoak mixed with air? If you have a problem in the pump or with a check valve, the air can push back through the high pressure line and through the pump.

 

[phred113]

My guess is that you have a check valve or solenoid that stuck open. Look at these parts and replace as necessary because they do not last forever.

 

[mjc3333]

You may have lost one of your 3 phase inputs to the HP pump. The pump will still turn over depending on which phase was knocked out. It could have been a temporary problem. You could have a problem with your motor starter in that bay also with one phase not working or making contact correctly.

 

[Earl Weiss]

MAke Sure you are not bypassing thru the unloader.