A commercial pressure washer is a system: water supply, pump, control circuit and—on a hot machine—the fuel and ignition side. Good diagnosis checks the sequence instead of changing parts at random.
Start with what the machine is telling you
Note exactly when the fault occurs. Does it happen with the trigger open or closed? Does the motor run? Is pressure steady? For a hot machine, listen for the burner fan, ignition and fuel solenoid. Smoke colour and timing can also narrow the search.
Safety first: isolate electricity, release stored pressure and let hot components cool before removing covers. Fuel and high-voltage ignition faults need competent testing.
Check the simple causes first
- Confirm a strong water supply and clean inlet filter.
- Inspect the nozzle, hose and trigger for restriction or damage.
- Check fuel level and obvious leaks.
- Record fault codes before clearing anything.
When to book it in
If the machine trips power, runs without stable pressure, leaks internally, produces persistent smoke or repeatedly fails to ignite, stop using it. Continued use can turn a serviceable fault into a pump, motor or boiler repair.