EXPLANATION OF PILOT VALVE
Figure 8 - Pilot Valve (Ref. No. 17, page 7)
NOTE: Pilot valve (Z-180) pressure
range is 140 to 170 psi.
Optional Pilot Valves
35- 40 psi
The Pilot Valve is designed to act as an automatic "on"
and "off" air switch. When in the "on' position, it allows
air to flow from the tank thru the tube to some device
such as a compressor head unloader mechanism, thus
actuating it. In the "off" position, this valve stops the flow
of air thru the valve and releases the pressure in the line
to the device.
The pilot Valve works as follows: Tank air pressure acts
on the bottom of the valve. When pressure is great
enough to overcome spring force holding valve down on
lower seat, it lifts off seat and allows air to flow around
valve and out through side opening in Pilot Valve. When
valve lifts off lower seat it moves up and seats on upper
seat where it is held by tank air pressure. When
pressure in tank and on valve drops, spring forces valve
back down on lower seat. Air in line to device being
actuated can then escape through upper seat and out
vent hole. The pressure at which the Pilot Valve is "on"
or "off" is controlled by the spring, which has been
installed at the factory. A small adjustment can be made
in the field by changing the spring force by compressing
the spring more or less with the adjusting screw provided
on the Pilot Valve.
The unload pressure is adjusted by turning the pressure
adjusting nut #1 clockwise to increase, and counter-
clockwise to decrease, pressure.
Changing the differential (difference there is between
load and unload pressure) is accomplished by holding
the lock nut closest to the body of the valve #2 so it does
not move, then turning the large nut #3 next to it very
slightly clockwise to increase the differential, and
counter-clockwise to decrease it.
IMPORTANT: REFER TO OPERATING MANUAL & SERVICE GUIDE, FORM 5S1408, FOR COMPREHENSIVE AIR