OPERATING FROM FIRE HYDRANT

TM5--4210-224-14&P

2-21. OPERATING FROM FIRE HYDRANT (Continued).

Turn engine throttle control knob (3, figure 2-1) counterclockwise to accelerate engine until master pressure

gauge (9) indicates desired discharge pressure.

CAUTION

As a precautionary measure, the master pressure gauge reading (9, figure 2-1) should not be

permitted to drop below 10 psig. This will permit a 5 psig error in gauge accuracy with the

danger of collapsing a water main. It may be necessary to sacrifice the discharge pressure in

order to prevent damage to a water main.

Turn pressure relief control knob (12, figure 2-1) counterclockwise to decrease pump discharge operating

pressure, clockwise to increase pump operating pressure.

CAUTION

Fire pump will heat up rapidly if pump is operated with all discharge valves closed. Prolonged

operation will cause damage from overheating.

NOTE

Periodically check engine temperature gauge (1, figure 2-1) for normal engine-operating

temperature range of 100F (55.5C) to 250F (138.8C).

If a shutdown is required for changing hoses or any other reason, slow the engine to decrease

water pressure to 30 psi and close the discharge valves. Open tank-to-pump valve control

handle (13, figure 2-1) and tank fill control handle (14) to recirculate the water.

Shut down fire pump by turning engine throttle control knob (3, figure 2-1) clockwise to throttle engine down.

Turn heat exchanger control switch (20, figure 2-1) to the "OFF" position.

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