Learning Event 2
STOP THE M12A1 PDDA ENGINE AND PUMP UNIT
After the mission has been completed, the unit must be shut down. You must accomplish this procedure
safely and without damage to the apparatus. To do so, you must be familiar with the components and
controls discussed previously and know the correct sequences of steps to perform.
STOPPING PROCEDURE FOR THE PUMP UNIT
To stop the pump unit, first reduce the engine speed to an idle by rotating the throttle counterclockwise.
Then, close the fuel shut off valve on the control panel, and close the finger nut on the sediment bowl
beneath the fuel tank. Next, shut off the ignition by turning the start-magneto switch to the stop
position. Shut off the fuel by turning the fuel valve fully clockwise. Close all valves, including drains
(valves 1, 2, 3, 4, and the tank drain valve).
STOPPING PROCEDURE FOR THE PUMP UNIT WHEN THE M2 WATER HEATER HAS BEEN
When the M2 water heater has been in use, certain precautions must be observed to avoid damage to the
apparatus or injury to personnel. To stop the apparatus, follow the stopping procedures in the
Step 1. Place the HEATER-ON/PURGE-ON switch to the PURGE-ON position. After combustion
ceases, operate for two minutes on PURGE-ON.
Step 2. Place the heater receptacle switch to the off position.
Step 3. Continue to cycle water through the boiler for at least three minutes or until the water
temperature is approximately 100 degrees Fahrenheit as indicated on the water temperature gage.
Step 4. Place the voltage regulator switch in the OFF position. Disconnect the main electrical power
cable. Install the cap over the socket receptacle. Stow the main electrical power cable in the storage
compartment of the M2 water heater.
Step 5. Disconnect the fuel supply and fuel return lines of the fuel hose from the M2 water heater.
Install the caps. Disconnect the fuel hose from the gasoline can. Drain the fuel hose and stow it in the
storage compartment of the M2 water heater. Install a cap on the fuel can.
Step 6. Stop the pump unit assembly as explained above.