10
When the pump is in the high pressure mode, the chemical
injector ball is forced against its seat, cutting off the siphon
effect and preventing water from back-flowing into the
chemical reservoir. Figure 2.7 depicts this high pressure
condition.
The chemical injector must be carefully sized for the system.
Too small of a venturi orifice will result in too low a
pressure and too much chemical will flow into the stream.
Too large an orifice will cause too much pressure at the
venturi throat and the injector will not work.
Easy Start Valve
Certain larger
Generac Portable Products®
pressure washers may be equipped with an easy start valve.
This patented device relieves pump outlet pressure during
engine cranking so that it is easier for an individual to pull
the recoil starter rope.
Figure 2.8 depicts a
Generac Portable
Products®
medium frame pump in its starting condition.
Inlet water is connected to the pump’s garden hose
connector. Air has been purged from the pump’s water
passages. The check ball is attached to its restraint magnet
(magnet not shown).
In this condition, the pump’s internal water pressure is at
garden hose pressure. Water is free to circulate throughout
the pump without restriction, thus permitting an easier pull
on the starter rope.
As soon as the engine starts, water flow forces the check
ball against its seat, closing the garden hose pressure water
passage. Pressure within the system becomes regulated by
the unloader valve setting and the nozzle restriction.
Section 2 • Pressure Washer Components
Portable Pressure Washer Familiarization and Troubleshooting Guide
Item
Name
1
Ball shown seated, cutting off chemical
flow
2
Chemical injection fitting
3
Siphon tube
4
Check ball seat
5
Venturi throat
Figure 2.8 — Starting Condition
Item
Name
1
Location of restraint magnet (not shown)
2
Check ball shown attached to magnet
3
Inlet water channel
Figure 2.7 — High Pressure Cut-off of Chemical Injection
System
