These valves are open when the handle is pointing toward outlet to hose; they can be used to drain air from the hose on
the reel by turning them 180 or shut off all air by turning 90.
15. Safety Valve
The safety valve is located on the air receiver, and is set to release excess air pressure between 120 and 125 psi. No
attempt should be made to change the pressure setting of the safety valve because this is the maximum pressure under
which the unit can be operated safely. The safety valve must be operated manually each day when starting the unit, and
also when air receiver pressure reaches about 70 psi to make certain that the valve is operating properly.
16. Hose Reel Lock Pin
Each hose reel is equipped with a locking pin assembly which prevents the hose reels from turning when the reels are
not in use. The locking pins are spring loaded and must be pressed in and turned to release the reels for operation.
17. Shutterstat
a.. Location. The shutterstat is located in the connection between the water pump body and the radiator. It consists of
a liquid bulb, thermostat element, and needle valve assembly, and has two air line connections. One air line is connected
through an air filter to the air receiver. The other air line leads to the air cylinder which operates the radiator shutters.
b. Purpose. At normal operating pressure, air passes through the shutterstat needle valve to operate the air cylinder.
This action closes the shutters against spring tension in the cylinder. When the temperature of the cooling water at the
shutterstat approaches 180 F, the heat is transmitted through the liquid bulb up to the thermostat element. The element
expands closing the needle valve and allowing the spring to open the shutters.
18. Ignition Switch
The ignition switch is mounted on the instrument panel. When the lever handle of this switch is snapped to the left
(ON), it completes the primary circuit leading from the battery through the ammeter to the ignition coil. The switch must be
turned on before pushing in the engine starting button, and shuts off the
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