Waterjet troubleshooting
Choose the problem you see. Each page lists the likely causes, what to check and which parts fix it.
Intensifier: high-pressure side
- Cutting pressure is lower than normal
- The pump runs but builds no high pressure at all
- Water drips from a weep hole on the HP cylinder or end cap
- Water leaks from the sealing head weep hole
- Water leaks at the sealing head gland nut (HP outlet)
- Hot water from the end cap weep hole (direct-drive and hard-seal end caps)
- A check valve or sealing head gets hot
- Overstroke alarm or the pump strokes too fast
- Pressure fluctuates or pulses
- Pressure with the nozzle closed is much higher than the set pressure
- HP seals wear out much faster than before
- Plunger is scratched, cracked or broken
- Suspected cracked HP cylinder
- Loud knocking from the check valve when the pump strokes
- Service is due: which maintenance kit do I need?
- Water sprays from the middle of the HP cylinder
- Backup ring or hoop is deformed or worn after a seal change
- Inlet water manifold or LP line gets hot
Intensifier: hydraulics & oil
- The pump does not shift or stops at the end of a stroke
- The pump shifts unevenly (one stroke longer than the other)
- No or low hydraulic oil pressure
- Pressure is erratic or cannot reach the set value (proportional control)
- Hydraulic oil gets too hot
- Oil-to-air cooler does not cool (fan or fins)
- Low oil level alarm
- Oil leaks from a weep hole on the hydraulic cylinder head
- Water in the hydraulic oil (milky oil)
- Hydraulic centre section runs hot or loses power
- Pump motor runs but the hydraulic pump does not turn
- Large pressure dips at every stroke change
- Hydraulic oil filter indicator or alarm
- Hydraulic oil is dark or smells burnt
- Hydraulic pump is noisy (whining or rattling)
- Oil leaks from a hose or fitting on the hydraulic unit
Direct-drive plunger pumps
- Low inlet water pressure shutdown
- Cylinder over-temperature warning or shutdown
- One cylinder no longer makes pressure
- Crankcase over-temperature
- Direct-drive pump is noisy
- Oil leaks from the crankcase
- Overpressure shutdown (pressure control valve)
- Direct-drive pump does not come up to pressure
- Drive belt squeals or wears fast
- Direct-drive pump vibrates more than normal
Inlet water, booster & filters
- Low inlet (cutting) water pressure
- Booster pressure drops a lot during each stroke
- Filter housing does not fill completely
- Water leaks around the filter cap or housing
- Boosted water temperature is high
- Short life of orifices and seals: check water quality
- Nozzle or HP line filter blocked or collapsed
- Booster pump does not run
- Shop air pressure too low for valves and feeder
Start, power & alarms
- Pump will not start
- Console display and lights are off
- Pump stops unexpectedly / motor overload trips
- Red alarm light flashing
- Pressure reading is wrong or jumps (sensor fault)
- Controller over-temperature
- E-stop cannot be reset
- Drive (VFD) fault or phase loss
On/off valve
- Water drips from the nozzle when the jet is off
- Water leaks from the on/off valve body or weep hole
- Air leaks from the valve actuator
- On/off valve opens or closes slowly
- On/off valve does not open
- On/off valve does not close (jet keeps running)
- On/off valve seats wear out quickly
- Water drips on the part at the end of the cut
HP tubing, fittings & swivels
- A high-pressure fitting leaks
- Fine mist sprays from an HP tube
- HP coil (whip) on the cutting head fails often
- HP swivel leaks or turns stiffly
- Bleed-down (dump) valve leaks while cutting
- Pressure stays in the line after stopping
- New HP tubes do not seal after making them
- HP lines shake or vibrate
Cutting head & stream
- The stream looks fuzzy, split or sprays
- Orifices wear out or crack quickly
- Stream comes out at an angle
- Water leaks around the cutting head body
- Pure water cutting: poor or slow cutting
- Stream suddenly stops or becomes very weak
- Focusing tube wears oval or on one side
- Focusing tube cracks or breaks
Abrasive feed
- Water or wet abrasive comes back up the abrasive hose
- The focusing tube keeps clogging
- No abrasive flow
- Abrasive flow is uneven or pulses
- Weak suction (vacuum) at the abrasive inlet
- Abrasive mini-hopper overflows
- Low abrasive alarm
- Abrasive hose wears through
Cut quality & parts
- Cutting is slower than before
- Jet does not cut through the material
- Too much taper (V-shape) on the cut edge
- Deep lines (striations) on the cut surface
- Rough or frosted edge at the top of the cut
- Burr on the bottom edge
- Corners are rounded or blown out
- Parts are not to size
- Marks at lead-in and lead-out
- Glass or stone cracks during piercing
- Composite or laminate delaminates
- Parts or material move during cutting
- Piercing takes long or blows back
- Small holes are not round or not to size
- Steel parts rust after cutting
Table, motion & catcher tank
- Axis motor fault or axis does not move
- Height sensor does not work
- Cutting head hit the material
- Catcher tank: splash, noise or chipping on parts
- Slats wear fast or parts fall through
- Tank water level does not hold or overflows
- Cable chain or hose guide is damaged