Start with water flow. Make sure the faucet is fully open, the garden hose is fully unwound and nothing is restricting the inlet. Then check the nozzle and inlet screen.
1. Give the pump a steady water supply
Westinghouse tells ePX3500 owners to fully unwind the garden hose and remove restrictions that reduce water flow. A kinked hose, partly closed faucet or plugged connector can starve the pump.
Read the garden-hose guide if the pulsing started after adding a longer hose, reel or connector.
2. Purge air from the system
With the washer off and the water supply on, squeezing the gun trigger lets water move through the system and helps clear trapped air. Follow your model’s startup procedure rather than jumping straight to the power switch.
3. Check the nozzle
Westinghouse includes nozzle cleaning in its maintenance instructions. A partly blocked orifice changes flow enough to create poor or erratic performance.
4. Check the inlet screen
The ePX3500 manual tells owners to remove and rinse the screens inside the garden-hose adapter periodically. If your water source carries grit or the machine has sat for a while, this is worth checking.
5. Stop if the simple checks do not change anything
If the water supply is solid, the inlet is clean, the nozzle is clear and the machine still surges badly, the diagnosis is moving beyond routine setup. At that point, use the manufacturer’s troubleshooting or support path for your exact model rather than buying random pump parts.
A fast isolation test
- Turn the machine off.
- Open the faucet fully and straighten the supply hose.
- Remove unnecessary quick-connects or a restrictive reel if practical.
- Check and rinse the inlet screen.
- Check the nozzle for debris.
- Purge air according to the startup procedure, then test again.
If the pulsing disappears after simplifying the water supply, you learned something useful without touching the pump.
Why the symptom can come and go
A marginal water supply may work with one nozzle but struggle with another condition, or it may behave differently when another fixture in the house starts using water. That is another reason to diagnose flow before assuming an internal failure.
Do not use the pump as a diagnostic guinea pig
Repeatedly running a machine that is clearly starved for water is not a useful test. Westinghouse warns against operating the pump without an adequate water supply.
Sources used for this answer
Back to class: Electric Pressure Washer Class.