Almost all first-day problems with a new pressure washer come from two things: running the pump without water in it, and disconnecting something while it is still under pressure. Both are in the sequence below, and both take seconds to avoid.
The two habits that matter most
1. Never run the pump dry, even for a few seconds. Pressure washer pumps are lubricated by the water passing through them. Running one dry damages the seals immediately and permanently, and it is the fastest way to destroy a new machine.
Which is why step six exists: with the machine off and the water on, squeeze the trigger until water flows steadily and the spluttering stops. That purges the air. Only then start the motor.
2. Release the pressure before disconnecting anything. Machine off, water off, then squeeze the trigger. The hose holds pressure after shutdown, and a fitting removed under pressure damages O-rings and occasionally travels across the yard.
Water supply is a real variable
A machine can only deliver its rated flow if the tap can feed it. Time how long a 5-gallon bucket takes to fill from your outside tap: under 60 seconds is comfortable for anything on this site. Much slower and your effective flow is below the machine’s rating.
Also: open the tap fully, keep the supply hose short and unkinked, use a 5/8-inch hose rather than a narrow one, and fit the inlet filter. A starved pump shows up as pulsing and weak pressure — won’t build pressure.
Electric machines: give it its own circuit
Plug it into a dedicated 15-amp outlet. Sharing with a freezer, a shop vac or a workshop circuit is the usual cause of a breaker tripping mid-job.
Avoid extension cords, and if you must, use a short heavy-gauge one. A long thin cord drops voltage, which makes the motor run hot and can trip the thermal cutout. If you need reach, use a longer hose, not a longer cord.
Gas machines: before the first pull
Check the engine oil level, which is often shipped low. Check whether the pump has its own oil and whether it is filled — pump oil. Fuel it with fresh petrol. Then open the water, purge the air, and only then choke and pull.
Never start a gas machine with the water off. The same dry-run rule applies and the consequences are the same.
Fit the widest nozzle first
The white 40-degree tip, every time you start. You can always step to a narrower one; you cannot undo a mark in your siding.
Pull the quick-connect collar fully so the tip clicks home, and tug it. A half-seated tip exits under pressure. Colors and what each is for are in the chart.
Then test on something that does not matter
A patch of concrete, an old fence board, a paving slab out of sight. You are learning three things: how hard the gun kicks, what distance actually cleans, and how quickly the spray marks a surface when you get close.
Five minutes here is why your first real job goes well. Then read the safety page and the common mistakes, and pick a job from surfaces and how-to.
After the first use
Flush any detergent out with clean water. Release the pressure. Drain the hose. And if the first freeze is anywhere in sight, do not put it away without winterizing it — a cracked pump usually costs more than the machine is worth.
