5
Operation of a pressure washer system may be briefly
described as follows. Please refer to Figure 1.1 for visual
component identification:
1. An inlet hose delivers water to the motor-driven, piston-
type pump. An inlet strainer (item 6) protects the pump
(item 5) against damage from solid impurities. The motor
driving the pump (item 9) may be gas or electric.
2. Rotary motion of the motor crankshaft is converted to
reciprocating motion of the pump’s pistons using an axial
cam.
On a piston’s ‘suction’ stroke, an inlet valve opens and
water is drawn into the piston chamber. On the piston’s
‘pressure’ stroke, that piston’s inlet check valve closes and
its outlet check valve is forced open so pressurized water
can leave the chamber. There is one inlet check valve and
one outlet check valve for each piston.
PRESSURE WASHER OPERATION
Section 1 • Operation
Pressure Washer Familiarization and Troubleshooting Guide
Item
Name
1
Spray nozzle
2
Hi-Lo nozzle collar
3
Spray gun extension wand
4
Spray gun with locking trigger
5
Pump, including optional thermal relief and/or
easy start valve
Item
Name
6
Inlet strainer
7
Unloader/pressure regulator valve
8
Chemical inject fitting (optional)
9
Engine on cart
10
High pressure hose
Figure 1.1 — Example Pressure Washer System
