TL;DR
Low intensifier output pressure is usually worn high-pressure seals, check valves, or a damaged intensifier cylinder. Inspect the check valve cartridges and HP seals before condemning the cylinder.
What you might see
- pump pressure does not reach operating setpoint
- pump cycles rapidly without building pressure
- visible water weeping at the intensifier end caps
- cut quality degraded at full commanded speed
Likely causes
Worn high-pressure end-cap seals allowing internal bypass
Contaminated or damaged high-pressure check valve cartridges not seating
Low inlet water pressure to the intensifier feed side
Intensifier plunger scoring from insufficient water filtration
Required tools
- High-pressure torque wrench (rated for the HP bolt torque)
- Intensifier seal kit (OEM or equivalent)
- Check valve cartridge replacements
- Pressure gauge (calibrated)
- Filter cartridge replacement
- LOTO kit
Safety first
- Never work on any high-pressure waterjet component without confirming zero pressure on a calibrated gauge.
- High-pressure fittings can eject at lethal force if loosened under pressure. Use the system dump valve to bleed the circuit completely.
- Wear eye protection when inspecting check valve cartridges. Springs and balls can release unexpectedly.
Procedure
- 1
Depressurize the entire high-pressure circuit and verify zero pressure on all gauges before touching any HP fittings.
Warning: Residual pressure above 1,000 psi can cause severe injury from fitting ejection. Bleed the system through the dump valve. - 2
Check the inlet water supply pressure at the intensifier feed port. It should meet the minimum supply specification for the Flow pump model.[1]
- 3
Inspect the inlet water filtration cartridge and replace if dirty. Contaminated supply water accelerates seal and plunger wear.
- 4
Remove the high-pressure check valve cartridges from both inlet and outlet ports on the intensifier end caps.
- 5
Inspect each check valve cartridge for pitting, scoring, or debris on the ball or poppet seat. Replace any suspect cartridge.[1]
- 6
Remove the end cap and inspect the high-pressure piston seal. Any extrusion or tearing of the seal lip requires replacement.
- 7
Reassemble with new seals and check valves, torque all end-cap bolts to the specification in the pump maintenance manual.
- 8
Prime the system and run up to operating pressure. Monitor pressure stability over 5 minutes to confirm the repair holds.
Sources
Flow International Flow Mach 200 / 500 / 700 Waterjet Cutting Machine general technical documentation, Flow International
Flow International intensifier pump maintenance documentation, high-pressure seal and check valve service (general)
More guides for Flow International Flow Mach 200 / 500 / 700
How to fix abrasive feed interruption on a Flow Mach 200 / 500 / 700 waterjet
Abrasive stoppages are usually a clogged abrasive line, empty hopper, or a worn or blocked metering orifice. Check the hopper level first, then inspect the abrasive line from hopper to nozzle.
How to diagnose and replace a worn orifice or nozzle on a Flow Mach 200 / 500 / 700 waterjet
A widening kerf, taper on cut parts, or reduced cutting speed nearly always means the orifice jewel or focusing nozzle is worn. Replace both as a set when cut quality degrades.
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