Section XIII. PUMPING SYSTEM

Section XIII. PUMPING SYSTEM

rewind button, located beneath the hose reel assemblies

121. General

on the instrument panel. The heat exchanger is mounted

The fire truck pumping system consists of a

in the engine compartment, and circulates water through

centrifugal-type pump, rotary vacuum priming pump,

the engine cooling system from the pumping system to

steady valve, relief valve, water tank, foam, and two

cool the engine. The primer oil tank is mounted on the

motor driven hose reels. A series of operating valves,

engine cab beneath the right-hand seat. It supplies oil to

drain valves, and a foam proportion regulator, regulate

the primer pump.

operation of the fire pump for pumping water, or a water

and foam combination.

The centrifugal-type pump

122. Primer Pump

develops pressure and capacity, by means of centrifugal

a. Removal.

force, and must be primed before it will lift water. The

priming system consists of a rotary vacuum pump

(1) Remove the primer pump motor and

operated by a 24-volt electric motor controlled through a

solenoid relay (para. 105).

manual priming valve which actuates a microswitch

(2) Refer to figure 59, and remove the primer

controlling the electric motor.

Water pressure is

pump from the water pump manifold.

controlled manually by a throttle knob and is held

b. Cleaning, Inspection., and Repair.

automatically by the relief valve. The relief valve is

(1) Clean all parts with an approved cleaning

adjusted to any pump pressure up to 300 psi. The hose

solvent, and dry thoroughly.

reels are electric motor driven, and actuated by a reel

Figure 5.9. Primer pump and universal joint, removal and installation.

TAGO 6839A