The controls and PLC (not pictured) control the valves in the hydraulic circuit to determine the pressure and flow of the hydraulic oil to and from the intensifier. Various sensor and proximity switches can also be integrated into the controls to monitor the entire pump to verify things like stroke rate, oil temperature and pressure, inlet water pressure and flow rate and more. This capability makes working with and troubleshooting the modern day intensifier much easier.

The pneumatic On-Off valve controls the flow of water to the cutting head. The On-Off valve at the cutting is "normally closed." That is, when there is no compressed air supplied to the On-Off valve, a needle fits tightly against a seat to stop any high pressure water from getting to the cutting head. When compressed air is supplied to the On-Off valve (i.e. "tool on" command from the control), the needle is forced up from its seating location and the high pressure water can flow through the orifice to the cutting head.

In, or near, the high pressure pump cabinet is another On-Off valve that works in tandem with the On-Off valve at the cutting head. The On-Off valve in the pump is typically called the Safety Relief valve. This Safety Relief valve in the pump is "normally open." This valve will stay open when there is no air supplied to it. When the On-Off valve at the cutting head closes ("tool off" command by control or no power to the system), the Safety Relief valve in the pump will open, relieving all water pressure from the high pressure tubing. When the "tool on" command is issued by the control, the Safety Relief valve closes so that all high pressure water will go to the cutting head. Note, not all manufacturers of new pumps have the Safety Relief valve as standard. We strongly suggest you ask your pump manufacturer if they supply this standard, and when it is activated. Again, some pump manufacturers will only activate the Safety Valve when an E-Stop is pressed; when the pump stops, high pressure lines are still pressurized.

Both of these On-Off valves must be in good working order to protect against accidental high pressure water discharge at the cutting head that could severely injure someone working on or near the cutting head or any of the high pressure lines. Periodic replacement of the needle, seat and associated parts is required to maintain these valves.