WATER
FLOW
GAL/MIN
PRESSURE DROP IN PSI PER 100 FT OF HOSE
WITH TYPICAL WATER FLOW RATES
(HOSE INSIDE DIAMETERS, INCHES)
1/4
5/16
3/8
1/2
5/8
3/4
1”
0.5
16
5
2
1
54
20
7
2
2
180
60
25
6
2
3
380
120
50
13
4
2
4
220
90
24
7
3
5
320
130
34
10
4
6
220
52
16
7
1
8
300
80
25
10
2
10
120
38
14
3
15
250
80
30
7
20
121
50
12
25
200
76
19
40
410
162
42
60
370
93
servicing unloader valves. The valve should be mounted
as close to the pump outlet as possible; do not use any
hose between the pump and the unloader.
Pressure Relief Valve
- A safety device which when
installed and set-up according to the manufacturer’s
specifications will open and dump to atmosphere a
quantity of water if the system becomes overpressurized
due to a failure of system components.
Pulsation Dampener
- Pulsation Dampeners are
installed in systems either to smooth out the pulsations
caused by the pump itself or to absorb pressure spikes
when the gun is shut off. A duplex pump may require a
pulsation dampener because of the pulsation not
experienced with a triplex pump. When there are long
runs of pipe, a pulsation dampener may be required to
soften the hammer effect when a gun is shut off.
Pressure Gauge
- Allows the equipment operator to
monitor the system for peak performance. A worn spray
tip will be evident with a decrease in system pressure.
High pressure may indicate a partially plugged spray tip
or other restriction, or a defect in the unloader valve.
Important factors in gauge selection:
• Liquid filled - to absorb the pressure fluctuations
in the system.
• Restriction orifice installed to avoid damage from
pressure “spikes”.
• Select a gauge so that normal system operating
pressure is in the middle of the gauge’s range.
Downstream Injector
- Introduces a cleaning chemical
into the water stream after or downstream of the pump.
Care must be taken to size the injector to the system
volume or GPM. Check with manufacturer’s literature.
Too small of an injector causes a large pressure drop
across the injector and injects a very high concentration
of chemical. Too large of an injector will not draw any
chemical. Downstream injectors require low pressure,
generally about 200 PSI, to activate the chemical flow.
A double nozzle holder, rollover nozzle, and a double
lance are a few accessories that allow mounting a low
pressure spray tip, as well as the standard high pressure
spray tip. An adjustable nozzle allows a large orifice to
be opened around the high pressure spray tip.
High Pressure Hose
- A required component of your
system. Be sure that the hose that you select to use is
compatible with all chemicals that will be introduced
into the system, is rated at least 50% greater
than the system operating pressure, has
good quality Permanite couplings on each end (do
not use hose clamps), and is as short as
possible to avoid pressure accumulation when
releasing trigger, and to minimize operating
pressure loss in hose.
7
If quick disconnect couplings are used on the ends of
the high pressure hose, be sure that they are of the
“straight through” design. Air type quick couplers with
internal “shut-offs” are not acceptable because
pylsations in the water flow will destroy the moving parts
and lodge them in the gun and/or spray tip.
Spray Gun
- Must be selected to withstand pressure,
volume, temperature and chemicals in the system. Guns
must be durable to withstand the kind of abuse typical in
pressure wash applications. Consider comfort to reduce
operator fatigue. Ease if servicability is also important.
There are many types and styles of guns available. Be
sure to “shop around” and select one that most closely
fits your needs.
INSTALLING YOUR
COMPONENTS
Refer to manufacturer’s printed literature and install
all components according to manufacturer’s
recommendations to avoid serious bodily injury or
property damage and to insure proper system
operation.
All plumbing and component parts must be of the same
size or larger than is on the inlet and outlet of your pump.
The thread sizes are a guide to the required
sizes of plumbing for proper water flow both in and out
of the pump.
All plumbing and component parts must have an
operating pressure rating of at least 50% above the
maximum rated output pressure of the pump, and should
have an actual burst pressure of 3-5 times the normal
system working pressure.
HOSE FRICTION LOSS
