Step 2. Wash down all interior and exterior surfaces of the tank unit assembly by using one of the
discharge hoses. Allow the residue to drain out of the open tank drain valve. Spray clear water to clean
any slurry deposits from the exterior of the tank.
Step 3. Connect the clear water supply to the agitator and flush the piping until it is clean.
Step 4. Leave the tank drain valve open after flushing the tank unit. When the tank is completely
empty, close the tank drain valve.
Step 5. Continue operating the pump and flush the upper and lower discharge piping and discharge
hoses until the water clears. Wash the exterior surfaces of the M2 water heater. Then shut down the
pump by pulling out the throttle to reduce engine speed.
Step 6. To prevent flooding, shut down the pump as follows: Close the fuel shut-off valve and let the
engine operate until dry. Place the start -magneto switch in the STOP position. Open the pump drain
valve. When the water stops running out, cap all pipes and close all valves except the pump drain valve.
Draining the M12A1 PDDA. When preparing the M12A1 PDDA for storage, the components must be
drained using the following steps.
Step 1. Position the tank unit assembly on sloping ground with the tank drain valve at the lowest end.
Open the tank drain valve and leave it open until the tank is empty. Then close the tank drain valve.
Position the M2 water heater on sloping ground with the drain (water inlet line uncapped) at the lowest
end. When the M2 water heater is empty, install the cap over the water inlet.
Step 2. Disconnect the suction hose from the suction hose connector. Elevate the foot valve end of the
suction hose until it is higher than the other end of the suction hose. Drain all of the water out of the
suction hose. Install the foot valve with its hose adapter in the bracket on the tank unit skid base. Fasten
the thumbscrew to hold the foot valve in place.
Step 3. Inspect the screen and the tank liquid level indicator inside the hopper-blender. See that they
are clean and are not clogged or coated with residual matter. Bolt the hopper cover and the hopper-
blender to the tank unit.
Step 4. Drain the blender hose and insert it inside the suction hose. Coil these hoses on top of the tank
unit inside the four retaining rods. Fasten hoses in place with the four bracket clamps. Coil the exhaust
pipe extensions on top of the tank unit. Inspect to see that the personnel shower assembly is stowed in
its retaining brackets on the tank unit.