Page 16-3
Pilot’s Operating Manual
Revision A1: Nov, 2002
Sub-section 16
WATER and WASTE
Hawker 800XP Pro Line 21
Section III - SYSTEMS DESCRIPTION
GENERAL
The water and waste system consists of a basin with heated running water located in a lavatory at the
rear of the passenger cabin and an electrically flushing toilet with external servicing facilities.
WATER SYSTEM
Wash water is stored in a 2.3 gallon heated water tank with a water pump controlled by operation of the
faucet.
LAVATORY WATER TANK
The water tank contains a triple element low voltage immersion heater, controlled to 40
°
C
±
2
°,
and
water level microswitches. Provided the tank is full, the water heater comes into operation immediately
when the TOILET WASH WATER push switch, on galley panel FG-A, is selected. The switch light
illuminates to show system operation.
The water level microswitches operate as follows:
• The high-level switch contacts are closed when the tank is full and open immediately the float starts
to fall.
• The low level switch contacts open when the minimum water level (just above the elements) is
reached to isolate water heater power supplies preventing overheating of the elements.
LAVATORY WATER PUMP
A counterclockwise rotation of the faucet will energize the pump for continuous operation until the faucet
is released. The pump is a self contained 12 VDC geared pump designed to prevent leakage and
contamination of the water supply and requires little maintenance. The pump boosts air pressure into
the water lines at 20 psig (approximately) above cabin air pressure.
Electrical power for the water pump is normally provided from busbar PS2 through the GALLEY
POWER and TOILET WASH WATER switches on the galley switch panel. For ground operation, the
system may be connected to the No. 1 battery through the ROOF/STEP light switch selected to the ON
position. Pushing the drain button allows the basin contents to drain away to a heated overboard drain
mast.
