GROUND FORCE 717H01, Operation & Maintenance Manual, Page: 45 / 57

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WATER TRUCK TROUBLESHOOTING
PROBLEM CAUSES SOLUTIONS
SPRAY HEADS
Spra
y head(s) ha
ve lo
w t
o no flo
w.
(Rigid frame trucks with
gr
ound speed contr
ol only
.)
The water control system
settings may be incorrect.
Set the spray mode to manual mode. Try the spray heads
and if they spray normally, then the water control system
settings may be set incorrectly. This setting is the speed
(in MPH) at which you want to have 100% water flow to the
spray heads. Refer to the Water Control System operations
manual on how to set.
Ground speed control is showing
truck is moving while the truck
is sitting still.
Realign the ground speed control radar. Check for obstruc-
tions in front of the radar lens.
The connection to the ground
speed is faulty and the
radar under the truck is not
communicating correctly.
Check the radar for misalignment, a bad fuse or damaged
wiring.
NOTICE
This is a 12-volt system.
The lens of the ground speed
control radar is dirty.
Clean off the dirt and protect the lens from dirt as much
as possible.
The control coil or solenoid may
be bad.
Check for a bad hydraulic cartridge(s) or coil on the
diverter valve. Repair or replace as needed.
The spra
y head(s) ha
ve
lo
w t
o no flo
w.
The spray bar full of debris. Remove the plugs on the end of the spray bar and remove
debris. It may be necessary to remove the valve cover
plate, diaphragm, spring and fan spray to clean out debris.
Apply pipe sealant to plugs before reinstalling.
There is a restriction or plugged
screen on the suction side
of the pump or in the pump's
impeller fins.
Remove the suction line going to the water pump and
check for debris. Check inside the tank to see if debris
is obstructing the suction screen of the sump. Remove
obstruction from the piping and screen.
The water pump is too slow. Set the chassis engine speed to full RPM (governed speed).
If the pump is still running slowly, there may be a hydraulic
issue. Refer to the HYDRAULICS section of this guide.
Ex
cessiv
e
w
at
er
flo
ws
back
int
o
the
tank whe
n the
pu
m
p is ru
nning,
and
spra
y he
ad
s are
clo
se
d.
Water hammer protection valve
could be faulty.
Check the water pressure by connecting a pressure gauge
to the spray bar, using a fitting on the inlet side of a spray
valve. With the spray heads turned off, increase chassis
engine RPM and check the water pressure. If it is below 60
PSI, check for a defective water hammer protection valve.
Internal plumbing could be
damaged.
Enter the tank and repair damaged plumbing.
If the damage was caused by freezing, drain the tank and
spray valves in the winter to prevent future damage.
WARNING
Follow all safety requirements for entry and welding inside the tank.
45
TROUBLESHOOTING