WARNING: Always lower the plow and
relieve pressure before removing any
lines or caps.
Remove the hex cap located on the rear of the
valve assembly.
The slotted screw underneath the cap is for ad-
justing the relief valve pressure setting. Turning
the screw clockwise increases the pressure and
turning the screw counterclockwise decreases
the pressure. Turn the screw in 1/2 turn incre-
ments until the pressure gauge indicates 2000
PSI +/-100 PSI, Home Owner and Steel Straight
Plows. 2200 PSI + / - 100 PSI, 10’ Straight
Plows. 2400 PSI + / - 100 PSI, Trip Edge and
Scoop Plows.
NOTE:
If no increase in pressure is observed
when turning the adjustment screw clockwise,
either the pump is weak (see “Hydraulic Pump
Test” page 24), the valve has dirt between the
valve ball and seat, or the spring is weak or bro-
ken. See Removal, Cleaning and Replacement
page 14.
Ensure the hex cap threads and O-ring are clean
and serviceable and re-install cap.
NOTE:
If the hex cap does not screw onto the
adjustment screw easily by finger, it is possible
that the adjustment screw is turning with the hex
cap and the pressure setting has changed.
See Testing procedure to ensure the adjustment
setting has not changed.
32 Adjustable Relief Valve Testing & Adjustment
