32
PI-121
January 2020
Section 7: Troubleshooting
7.0 40K MULTI-MODE VALVE TROUBLESHOOTING
Problem
Remedy
Constant Pres-
sure Mode or
Shut-In Mode:
No high pressure
water flows to gun
when triggers are
squeezed, but the
system pressure
is unchanged,
or nearly un-
changed...
To diagnose exact cause:
1. If air pressure gauge on Multi-Mode Valve is below
80 psi when gun is rotating, increase air pressure by
turning regulator knob clockwise, or increase pres-
sure from the air supply source.
2. If air escapes from anywhere other than the exhaust
port below the handle of the gun’s air motor, or a
small amount of exhaust from the air motor through
its front, check that all hoses are correctly connected
or repair any air leaks that are found.
3. If no air leaks are found, or if the problem persists,
disconnect one end of the air tubing that connects
the top of the brass pilot valve and the rear of the
aluminium air cylinder by pushing the ring of the
fitting down while pulling the tubing away from the
fitting. Squeeze gun triggers and check to see if air
begins to escape out of the top port of the brass pilot
valve. If air does not begin to flow, this indicates that
either insufficient air pressure is returning from the
gun to the end of the pilot valve, or the pilot valve is
not functional. If this is the case:
• Check that air pressure gauge reads at least 80
psi while gun triggers are squeezed.
• Check thoroughly for air leaks.
• Disconnect tubing from pilot port of the brass
pilot valve and install a pressure gauge. Squeeze
gun triggers and check pressure reading. Air
pressure returning through the signal line from
the gun to the Multi-Mode Valve should be at
least 25 psi.
• If pressure is 25 psi or above but the pilot valve
still fails to shift, then the valve is defective.
Replace brass pilot valve.