(5) When the tank is full, close the valve in the water source line, remove the filling hose, and close the water tank
manhole cover.
b. Filling the Tank With the Pumping Unit.
(1) Move the water distributor within easy reach of the water supply.
Note. Place the water distributor so that the suction lift is not more than 25 feet. The water pump will deliver a
greater volume of water at a lower suction lift.
(2) Remove the suction hose from the storage racks on the distributor frame.
(3) Remove the suction cap (12, fig. 4) from the suction tee and attach the necessary length of 4-inch hose to the
suction line and tighten.
(4) Install the suction strainer and foot valve (13, fig. 4) on the end of the suction hose to keep debris from entering
the suction hose.
(5) Submerge the end of the suction hose (5, fig. 9) in the water source.
(6) Turn the suction valve (17, fig. 4) and the two spraybar control levers to OFF. Turn the discharge valve control
lever to ON.
(7) Open the water tank manhole cover (1, fig. 2). Start the engine and water pump (para. 34) and fill the water tank.
(8) When the tank is full, stop the engine and water pump (para. 35) and close the water tank manhole cover.
(9) Turn the discharge valve control lever to OFF.
(10) Remove the suction hose (5, fig. 9) and install the cap (12, fig. 4) on the suction line tee (18) tighten securely.
(11) Clean the suction strainer.
(12) Stow the suction hose and strainer in position on the water tank.
c. Operating as a Sprayer.
(1) General. Water spraying is the primary function of the water distributor. There are two methods of spraying:
(a) Pressure-spray. The water pump (6, fig. 4) pumps the water from the water tank (7) through the spray-
bars (14). The pump pressure forces the water through any desired length of spraybar. The pressurean be
c
varied by regulating the engine speed with the governor control.
(b) Gravity-spray. Spraying can be accomplished through the spraybar with the flow of water from the tank by
gravity. This method does not permit the operator as much control over the amount of water sprayed, since
the water pressure cannot be varied.
(2) Regulating water pressure.
(a) The engine governor control (3, fig. 11) sets the engine speed, which controls pump pressure. For fire fighting,
adjust the engine speed to themaximum governed speed for greatest pump pressure.
(b) In gravity spraying, the discharge control valve lever (15, fig. 11) controls water pressure. Opening the valve
increases the pressure and closing the valve decreases the pressure.
(3) Attaching spraybar extensions. The spraybar extensions, which will increase the total spray pattern width from 8 to
16 feet, in one foot increments, (3, fig. 12). Couplings to connect the spraybar sections are also stored in the tool
box. The spraybar sections sh uld be screwed into the couplings until they are snug and alignment of the nozzles
o
is obtained.
(4) Use of water application chart. The controlled amount of water sprayed over a given area depends on three major
factors: water pressure, truck speed, and spraybar length. These factors are listed and cross-referenced in the
application chart, table I.
(a) Determine the working width of the spraybar to be used.
(b) Use pressure and travel speed recommended in table I for desired application. Use the 10 psi chart for all light
applications, and the 30 psi chart for all heavy applications, to permit a more satisfactory speed of truck travel.
AGO 6871A
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