FLUID SYSTEM DIAGNOSTICS - Trigger Gun/Spray Nozzle
PROBLEM
POSSIBLE CAUSE
SOLUTION
No nozzle flow from nozzle
when trigger depressed.
Broken piston rod in trigger gun
If water flows through discharge hose without gun, check trigger gun valve piston rod and
replace if necessary.
Missing metal insert in trigger gun
(European style gun)
Inspect to assure insert is in place.
Blockage in system past gun
Check nozzle or spray accessory for blockage and clear it.
Excess pressure when
trigger gun is released
Excessive pressure spikes
After unloader increases pressure to a maximum, further adjustment will only increase the
pressure spikes. Re-adjust.
Flow not stopping when
trigger gun released
Broken return spring on trigger gun If trigger action is too loose, return spring may need replaced.
Debris in gun valve
Debris in gun valve can stop piston return. Clear debris.
Trigger action sticks
Keeper plug too tight
It may be possible to loosen plug slightly without leakage but it will likely need replaced.
Trigger gun leaks
Worn or bad o-ring
Check trigger gun o-rings for ware or damage and replace.
Stripped or loose connections
Physical damage may not be apparent but unseen warping from freezing or sever overpressure
may still cause leaking.
No chemical
Chemical valve closed
Black nozzle
Open chemical valve. If It chatters with no chemical delivery, air is being drawn from the
upstream side of the pump. Check fittings, connections and ensure the inlet line is fully
submerged into the chemical jug.
Chemical dried up in the injector
Inspect and clean as necessary.
Chemical foot strainer clogged
May be a strainer or check valve. Ensure that the ball is not stuck or clogged.
Chemical line kinked
Chemical line kinking or binding prevents chemical delivery.
Chemical line too long
An overly long chemical line can prevent the pump from drawing chemical into the system. Try
installing a shorter line.
Chemical too dilute
Verify chemical strength.
No adjustment for low pressure
Downstream injectors only - Low pressure is required for most injectors to draw chemical. If no
adjuster exists it may need low pressure spray nozzle installed on the lance.
Incorrect injector orifice
If not properly sized for the systems rated output, chemical delivery problems will result. Check
serial plate for specs.
Excessive chemical
Valve improperly adjusted, check
knob on injector
To properly adjust, a chemical flow meter may be used to precisely measure chemical flow.
Chemical dilution to strong
Verify chemical strength.
Spray pattern irregular
Clogged nozzle
Spray pattern will be distorted if nozzle is clogged.
Volume proper, pressure
low
Nozzle to large
Ensure that the nozzle is sized properly sized for the system
Internal nozzle wear
A loss of pressure may result form gradual nozzle wear. Replace a nozzle of correct size.
Pressure proper, volume
low
Clogged nozzle
Spray pattern will be distorted if nozzle is clogged. Check nozzle for clogging if the unit has a
pressure unloader.
