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TM 5-4210-220-12
1-9 LOCATION AND DESCRIPTION OF MAJOR COMPONENTS. - Continued
n.
Firefighting System - Continued
(3)
The fire pump is a single-stage centrifugal-type pump. It is mounted to the frame on the left side. The
pump is driven by the engine via a Power Take Off (PTO) gear and a reverse mounted reduction gearbox. The PTO is
equipped with an electrically controlled, hydraulically engaged clutch. A control switch for engaging the clutch and pump
drive is located in the cab. Control of the pump flow and pressure is obtained through control of the engine speed. A
governor (throttle control) switch for this purpose is located in the cab and a throttle regulator is provided on the structural
control panel.
(4)
The pump may be used for water or foam mixture. Foam concentrate is drawn into the water flow via an
eductor and mixed as it passes through the pump. The pump may also be used to draft water via the 6-in suction ports
on the pump body. The pump is fitted with an automatic priming system.
(5)
An air-operated tank valve is used to control the delivery of water from the tank to the pump. Discharge of
water from the handline ports and turrets is controlled by manually operated ball valves. A relief valve is installed in the
pump discharge manifold to relieve excessive pressure. A manually operated drain valve is provided between the tank
valve and the tank.
(6)
Air-operated valves are used to control delivery of foam from the tank to the water eductor and for flushing
of the foam system subsequent to use. Proportioning of foam agent into the water system is controlled either by a
metering valve located in the cab or a similar valve located on the right hand side of the pump body front panel. A
manually operated drain valve is provided between the foam tank valve and the tank.
(7)
The roof and bumper turrets are manually controlled and operated from inside the cab. A direct linkage
from each turret to separate control handles provides the operator with side sweep and elevation control. Discharge
patterns from each turret are individually controlled by separate control levers.
(8)
The fire hoses provided consist of 1-1/2-in and 2-1/2-in hoses equipped with couplings for attachment to
outlet ports and separate nozzles. A selection of five nozzles is available to accommodate different flow, pressure, and
spray pattern requirements.
1-16
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