Originally Posted by
Signmaker
Have you checked the hydraulic valve block inside the pump cabinet?
On our machine there is a primary valve assembly just inside the front acess panel. There are two components on the block assembly; a turn wheel and a solenoid valve. The turn wheel adjusts the oil pressure into the LP assembly up top. The solenoid opens and shuts the oil flow into the LP cylinders. If you are having miss stroking issues it could be a failing relay on the solenoid or a loose wire. The oil flows through the block and dumps back into the main oil tank when not under load- when you need to generate HP water the solenoid flicks the valve and oil is diverted up into the LP cylinders---> stroking begins---> high pressure water is generated.
We had a problem of the pump miss timing strokes or in one case simply refusing to stroke at all---> we traced the issue to this solenoid assembly.