TEST OR INSPECTION
If system air pressure is below 85 psi (586 kPa), start vehicle engine and allow system
air pressure to build to at least 85 psi (586 kPa) (TM 9-2320-347-10). Shut off vehicle
engine (TM 9-2320-347-10). Disconnect air lines at water tank drain valve. While an
assistant puts pump operator's panel WATER TANK DRAIN switch to OPEN and
CLOSED positions (WP 0004), check if air pressure is present at water tank drain valve
blue and red air lines.
If there is air pressure, replace water tank drain valve (WP 0279).
Remove rings, wristwatches, neck chains, and any other jewelry before working
around vehicle. Jewelry can catch on equipment and cause serious injury. Jewelry
and tools may short across electrical circuits and cause damage to equipment, or
severe burns or electrical shock to personnel.
Put WATER TANK DRAIN switch to CLOSED position (WP 0004). Connect air lines at
water tank drain valve. Disconnect valve control wire harness water tank drain control
valve connector. Put pump operator's panel WATER TANK DRAIN switch to OPEN
position (WP 0004). With a test lead set, check for 22 to 28 VDC between valve control
wire harness wire 4053 (brown) at water tank drain control valve connector, terminal 1
and a known good ground.
If 22 to 28 VDC are not present, go to Step 6.