Glossary of Pressure Washer Terms

Adjustable Spray Wand

Some models are equipped with an adjustable spray wand that you can adjust the spray angle by turning the tip.

Automatic Cool Down System (Thermal Relief)

Cycles water through pump when water reaches 125 - 155 degrees F. Warm waterwill discharge from pump onto ground. This system prevents internal pump damage.

Axial Cam

A device (cam) used to transform the rotary motion of the motor/engine into the reciprocating motion of a pump's pistons.

Detergent Injection System

Cleaning detergents are drawn into water stream to make cleaning more effective by allowing detergents to saturate the soiled surface.

GPM

A unit of measure for water flow, same as "gallons per minute."

High Pressure Outlet

Connection for high pressure hose.

HP

Same as horsepower, a unit of measure for work.

OHV

Same as "overhead valve", an improved way to control exhaust and intake valves on internal combustion engines.

PSI

A unit of pressure, same as "pounds per square inch."

Purge

A method of eliminating air from a pressure washer so that starting the engine is easier.

PW

Same as "pressure washer."

RPM

Same as "revolutions per minute." The amount of revolutions (turns) an engine makes in one minute.

Side Valve

A type of internal combustion engine that uses a conventional "L" type cylinder head with the exhaust and intake valves on the side of the engine.

Spray Gun

Controls the application of water onto the cleaning surface with a trigger.

Thermal Relief

A technique use to reduce the build-up of high temperature water within a pressure washer pump caused when the spray gun trigger is closed.

Turbo Nozzle

A device used to increase the effectiveness of high-pressure water, by spinninga narrow stream of water in a circle at a high speed.

Unloader

A device used to relive the water pressure within the pump whenever spray flow is blocked.

Variable Pressure Control

A pressure washer feature that adjusts the water pressure to the specific cleaning task.