TM-9-2320-328-13-P-1
HEMTT-BASED WATER TENDER (HEWATT)
TECHNICAL MANUAL; OPERATOR’S AND FIELD LEVEL MAINTENANCE MANUAL (INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST); PART 1 OF 3
MARCH 2009
TM-9-2320-328-13-P-1 - Page 60 of 1318
TM 9-2320-328-13&P-1
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DRAFT
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NOTE
•
Foam system will not operate properly with intake pressures higher than 5 psi (34 kPa).
To facilitate operations from either a fire hydrant or from relay pumping, the automatic tank
refill should be used.
This system allows continuous pumping from onboard water tank
with accurate water/foam concentration levels.
•
The foam system can be operated from the cab for bumper turret and under truck nozzles
operations, and the pump operator’s panel for side discharge, hose reel, and flushing
operations.
WINDSHIELD DELUGE SYSTEM
The windshield deluge system supplies water to the nozzles mounted below the windshield, to clean the windshield
during firefighting missions.
The water is drawn from the onboard water tank by a 24 VDC electric pump.
The
windshield deluge system is operated from cab instrument panel.
ELECTRICAL SYSTEM
The HEWATT’s electrical system is powered by 12 and 24 VDC circuits.
12 VDC powers the radios and battery
charger circuits, and 24 VDC powers the valve control, emergency lighting, and scene (work) light pressure
governor circuits.
Power for these systems is provided by the HEMTT chassis batteries.
AIR SYSTEM
The HEWATT’s air system provides air pressure for valve control.
The air pressure for this system is provided by
the HEMTT chassis air system.
The HEMTT chassis air system is protected by an 85 psi (586 kPa) pressure
protection valve.
System air pressure must be above 85 psi (586 kPa) for valve operations.
WINTERIZATION PACKAGE
A winterization package is provided, to allow operation of the water pump and foam systems in temperatures down
to -25°F (-32°C).
The package uses a diesel-fired 27,300 BTU heater to heat the pump house, when the ambient
temperature in the pump house is below 39°F (4°C).
Note, the HEWATT vehicle should be stored in a controlled
environment with an ambient temperature above 55°F (13°C) when the water and foam tanks are filled and prior to
any cold weather firefighting missions.
END OF WORK PACKAGE
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