A machine can show pressure for a moment yet lose it as soon as water flow is demanded. Diagnosis should separate a restricted supply from pump wear, a mismatched nozzle and pressure-control faults.
Watch what happens at the trigger
Pressure that starts strongly and fades can indicate water starvation or internal bypass. Pressure that never rises may point to a badly worn nozzle, open unloader or damaged pump components. A gauge that looks healthy with the trigger closed does not prove useful working pressure.
Check the inexpensive causes first
- Adequate tap flow and an unrestricted inlet hose.
- A clean water filter and no trapped air.
- The correct nozzle size in usable condition.
- No leaks from the high-pressure hose, trigger or fittings.
- Detergent control fully closed when testing pressure.
Pump and unloader checks
Worn or dirty inlet and delivery valves reduce how effectively each piston moves water. Damaged seals can leak externally or bypass internally. The unloader must move freely and divert water correctly when the trigger closes; changing its setting without pressure and flow measurements can create a dangerous over-pressure condition.
Arrange a pressure and flow test →
Send the model and symptoms, or ask us to help match a machine to the work.