Bombardier DHC 8-400 (PWC PW150) Potable Water & Waste Systems PDF

BOMBARDIER DHC 8-400 (PWC PW150) ATA 38 - WATER & WASTE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS POTABLE WATER SYSTEMS GENERAL DESCRIPTION The potable...

BOMBARDIER DHC 8-400 (PWC PW150) ATA 38 - WATER & WASTE TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY B1/B2 MAINTENANCE TRAINING MANUAL Issue 6 - January 2023 Page 1 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS POTABLE WATER SYSTEMS GENERAL DESCRIPTION The potable water system supplies heated or unheated water to the galley. The water is used for drinking or washing purposes. On aircraft with the water system G1 galley (825CH01386): The water system supplies heated water to the galley for in-flight catering and unheated water for flight attendant sanitary purposes. All components are installed above the floor inside the galley enclosure. The system is remotely serviced from an external panel. SYSTEM OPERATION The potable water system has a 55 litre water storage tank and a 6 litres hot water (boiler) tank. An electric motor driven gear pump supplies system pressure. The system has: • • • Two hot water taps One cold water tap One sink The temperature of the hot water is approximately 91°C. All water lines and components are heated by either electric heating elements or heater cuffs. There is an optional overnight freeze protection system. External AC power operates heaters installed around the main components and water lines. This allows the water to remain in the aircraft overnight during freezing conditions. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 2 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - POTABLE WATER SYSTEM DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 3 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS from running dry. A filter installed upstream of the pump prevents foreign objects from entering the pump and contaminating the system. POTABLE WATER SYSTEM Two thermistors monitor the water temperature in the boiler. Thermistor MZ1 controls heater operation between 0°C and 91°C. If the temperature is below 0°C, MZ1 does not allow the heaters to operate. SYSTEM OPERATION CONTINUED A ground service cart is used to fill both tanks at the same time. The supply line from the cart is attached to the fill adapter on the external service panel. The T-handle on the panel is turned 90° in a clockwise direction. The T-handle is connected to the valve control unit located just behind the service panel. The control unit changes the turning movement of the T-handle to the linear movement of a cable which opens the filler valve. Once the valve is opened, water flows into the fill line for the tank and boiler. A flow restrictor in the fill line to the tank makes sure there is no increase in pressure in the tank or boiler during the filling process. The tank and boiler both have pressure relief valves to prevent overpressure. A check valve in the fill line to the boiler prevents any reverse flow through the fill adapter at the ground service panel. Water pressure during filling opens the check valve which allows water to flow into the tank and boiler. This prevents heater operation with ice in the tank. If the temperature is above 0°C, MZ1 switches the heaters on. Once the water temperature reaches 91°C, it shuts off the heaters and keeps the water temperature at this temperature. A second thermistor, MZ2, controls the READY light on the control panel. Thermistor MZ2 turns the READY light on when the water temperature is 91°C. As the hot water is used, the READY light stays on until the water temperature falls to 83°C, then MZ2 turns the light off. A thermal limiter switch supplies over-temperature protection, limiting the water temperature to 115°C in case of failure of the MZ1 thermistor. A red reset button in the middle of the thermal limiter pops out during an overheat condition. Only maintenance personnel can reset this button. A low level sensor shuts off the heater elements and illuminates the LOW WATER light when the water level is too low. A control panel on the face of the galley has an illuminated switch (ON/OFF), a LOW WATER light and a green READY light. Selection of the ON/OFF switch on the control panel in the galley area primes the electric motor driven gear pump. The switch latches on a 5 second relay, which allows enough time for the pump to build up pressure and turn on the green READY light. Power is supplied from the R SECONDARY bus. Once the pump is primed, flow control reverts to a pressure switch in the pump. This pressure switch will only operate if the pump is first pressurized by priming. With the heater elements powered, the first cycle time, for a cold tank to the READY light on, is just over 5 minutes. Subsequent cycle time is just over 4 minutes. When the hand wash faucet or a hot water tap is opened, the pressure switch in the pump senses the drop in pressure. The pump then begins transferring water from the tank into the boiler. Pumping will continue until the tap is closed by the user. A low pressure switch in the pump senses low pressure and turns the pump off to prevent it TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 4 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - POTABLE WATER SYSTEM SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 5 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS POTABLE WATER SYSTEM SYSTEM OPERATION CONTINUED Waste water from the sink is dumped overboard through the drain mast installed in the underside of the aircraft. An air-stop valve in the sink drain line is opened by the force of the waste water. The valve is normally closed to prevent cabin pressure from venting through the drain during flight. On the ground, pulling the T-handle and rotating it 90°counter clockwise drains the system. The drain valve opens allowing all water in the system to dump overboard through the drain mast. Once the system is drained, the handle is centred and pushed in. A ball valve is located in the line downstream of the tank. This valve allows the lines to be drained for maintenance purposes without having to drain the tank. Heater cuffs protect the fill and drain valves, the pressure relief valve, the filter, the pump, the check valve and the tank from freezing during flight. The cuffs are either moulded directly to these components or are fastened by bolts. The drain mast and water lines have built in heaters. All the heaters have thermostats which control the temperature in the individual components. The heater system is energized as soon as AC power is connected to the aircraft. This prepares the system for filling by preventing flash freezing of cold water coming into contact with cold components. There is an option for a freeze protection system to be run using external AC power. This is so the wash water and galley water systems do not have to be drained if the aircraft sits for extended periods of time overnight in freezing conditions. The system is designed to work to a minimum temperature of -30°C. Below this temperate, the system must be drained. This optional system has an extra relay. When external AC power is connected, the relay is energized using DC power from either the battery bus or from a ground power unit. Once the relay is energized, the aircraft AC bus is bypassed and only the lavatory and galley heaters are energized. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 6 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - POTABLE WATER SYSTEM SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 7 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS A 20w line replaceable heating element with a built in thermostat is moulded directly on to the valve body. The heater uses 115V AC variable frequency and the temperature is controlled between 10°C and 30°C. POTABLE WATER SYSTEM CHECK VALVE COMPONENT LOCATION AND DESCRIPTION TANK The 55 litre welded stainless steel tank, installed in the galley, stores potable water. The tank is filled through the fill port in the external service panel. An overflow line is located just below the fill port in the tank. The arrangement leaves 10% of the capacity unused to prevent structural damage if ice forms in the tank. A vent and pressure relief valve on top of the tank protects the tank from overpressuring during refilling. A tank drain port is located at the low point of the tank to make sure there is no residual water in the tank after draining. There is a sight glass on the front of the tank for a visual indication of the water level and an access cover which allows hand cleaning of the tank. FILL VALVE The check valve prevents the water in the heater from flowing back into the tank. A check valve is installed in line between the tank and the heater. The head of water in the tank forces the water through the check valve into the heater during the filling process. DRAIN VALVE The drain valve allows the entire system to be drained to prevent freezing in cold temperatures. The drain valve is a 2 position, 3 way ball valve, mechanically actuated from the rotary control box located at the ground service panel. A heating element is moulded to the top of the valve. A built in thermostat controls the temperature of the heating element between 10°C and 30°C. The heater element uses 115V AC variable frequency power. PUMP The fill valve allows water to flow if greater than 15 psig from the Service Panel fill line to the tank. It also allows overflow water from the tank to flow through to the drain mast. The heated fill valve is a 4 way, 2 position valve. The valve is mechanically operated from the rotary control box located at the ground service panel. In the open position, the valve allows water to flow from the fill line to the tank. It also allows overflow water from the tank to flow through to the drain mast. In the closed position, the valve isolates the tank from outside ambient pressure. Two internal vents in the valve break the vacuum in the fill and overflow lines allowing water trapped within the valve to drain away. The pump supplies pressure to move the potable water. The pump is a constant displacement gear type driven by an electric DC motor. It supplies a constant pressure of 20 psig (138 kPag) at a flow rate of 1.5 gal/min (0.68 L/min). The pump has a built in pressure regulator, check valve, flow sensor, pressure relief valve and pressure switch. A magnetic clutch connects the motor to the gear drive. At a specified torque, the clutch disconnects and allows the motor to free spin. An external heating cuff installed on the gear housing keeps the pump from freezing. HEATER ELEMENT The heater element prevents water in the fill valve from freezing. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 8 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - POTABLE WATER SYSTEM DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 9 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS The electrical box has a relay, transformer, circuit breakers, circuit board with self diagnostics and an LED display. It is also installed using quick release fasteners. POTABLE WATER SYSTEM COMPONENT LOCATION AND DESCRIPTION CONTINUED FILTER The filter removes contamination from the water upstream from the pump. The filter is sintered stainless steel woven wire mesh inside a stainless steel case. It has a nominal rating of 40 microns, 75 microns absolute. This prevents damage to the pump or clogging of other parts of the system. The filter is reusable and can be cleaned by back-flushing or ultrasonic cleaning. The filter is heated by an external heater cuff. The diagnostic LED on the electrical box come on when the control relay and elements are energized to heat the water. They remain on until the correct temperature is reached. If an LED does not come on, there is a fault with that heating element or with the power supply. When the correct water temperature is reached, the control relay is de-energized shutting off the heating elements and the LED. A PRESS TO TEST switch overrides the control thermistor, allowing the heating system to re-energize and the LED to come on. If the low level light is illuminated, the PRESS TO TEST switch will not work. The diagnostic feature is for maintenance use only. The switch panel kit consists of an ON/OFF illuminated switch (yellow), a READY light (green) and a LOW WATER light (amber). The switches and indicators are oblong in shape and have diffusers. DRAIN MAST The heated drain mast drains waste water from the sink and clean water from the lavatory system. The drain mast has two drain lines attached to it. One line drains the waste water from the sink while the other line drains the clean water from the system. A fibreglass/silicon blanket with a built in heater covers the two lines. A similar heater with a thermistor is attached to the drain mast. The two heating circuits are connected in parallel. The thermistor reduces the current to the heater as the temperature increases. BOILER ASSEMBLY The boiler assembly heats water from the tank for in-flight catering. The boiler assembly has a 6 litres tank, an electrical box, a control panel, interconnecting plumbing and electrical connections. It uses 115V AC 3 phase power to heat the water. The tank has 6 heating elements, 2 thermistors, a level sensor, float valve, pressure relief valve (65 psig) and a thermal limiter. The tank is installed using quick release couplings and fittings. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 10 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - POTABLE WATER SYSTEM DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 11 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS POTABLE WATER SYSTEM COMPONENT LOCATION AND DESCRIPTION CONTINUED GROUND SERVICE PANEL On aircraft with the pressure filling system (812CH00007): The ground service panel lets the ground service crew control the filling and draining of the water. The ground service panel has a fill adapter, a T-handle and a cable control unit. The cable control unit has a control box installed behind the ground service panel with two cables coming out of it. One cable is connected to the fill valve and the other is connected to the drain valve. Rotating the handle causes an inner cog in the control box to engage the cable and move it in or out. This action operates the fill valve and allows the system to be filled with water. Pulling the handle out disengages the inner cog and allows the handle to engage an outer cog. Rotating the handle then operates the drain valve in a similar way. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 12 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - POTABLE WATER SERVICE PANEL DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 13 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS POTABLE WATER SYSTEM INTERFACES The potable water system has the electrical interfaces that follow: • • • • • The pump is powered from the R SECONDARY bus through a 5A circuit breaker The start up 5 second time delay relay is powered from the R SECONDARY bus through a 5A circuit breaker The boiler is powered from the right AC contactor box 3 phase 115V AC The freeze protection heaters are powered from the 115V AC VARIABLE FREQUENCY RIGHT BUS through a 10A circuit breaker TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 14 of 48 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 15 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS WASH WATER GENERAL DESCRIPTION The wash water system supplies warm water to the lavatory sink for use by the passengers and crew. The lavatory water system allows passengers to wash their hands in the lavatory with warm water. All components are installed below the sink in the lavatory compartment. Servicing is done through a service panel installed on the exterior fuselage. The DC electrical system supplies power to the switches, valves and sensors which operate the lavatory water system. The AC electrical system supplies the power necessary to heat the system. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 16 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY WASH WATER SYSTEM SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 17 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS A switch and a control box are located near the faucet. Opening the faucet causes the switch to close which starts a time delay relay. The relay, which is located in the control box, energizes the pump for 5 seconds. As the pump is energized, warm water flows out of the heater to the faucet. The pressure of the flowing water opens a float valve in the faucet allowing the water to flow into the sink. After 5 seconds, the pump is no longer energized and the water stops flowing. WASH WATER SYSTEM OPERATION The lavatory water system has a 27 litre water storage tank and a 1.7 litre heater tank. An electric motor driven gear pump supplies system pressure. The system has one faucet with a built in switch which activates the pump. The temperature of the hot water is approximately 34°C. All water lines and components are heated by electric heating elements. Waste water from the sink is dumped overboard through the drain mast installed in the underside of the aircraft. An air-stop valve in the sink drain line is opened by the force of the waste water. When the water stops flowing, the air-stop valve closes to prevent cabin pressure from venting through the drain during flight. A filter installed upstream of the pump prevents foreign objects from entering the pump and contaminating the system. Waste water is drained from the sink directly overboard through a drain mast installed in the underside of the aircraft. There is also a manual drain operated from the external service panel. This allows ground crews to drain the system for overnight storage in freezing conditions. The heater uses a thermostat controlled electric blanket to maintain the water temperature at approximately 34°C. A thermal fuse limits the water temperature to a maximum of 60°C, in the event of a control thermostat failure. There is an optional overnight freeze protection system. External AC power operates heaters installed around all the components and water lines. This allows the water to remain in the aircraft overnight during freezing conditions. A solid state low level switch shuts off the heater blanket and the pump when the water level is too low. The low level switch also turns on the LOW LEVEL POWER CUT-OFF light located on the lavatory control panel below the sink. A ground service cart is used to fill the 27 litre storage tank. Heater cuffs protect the fill and drain valves, the pressure relief valve, the filter, the pump, the check valve and the tank from freezing during flight. The supply line from the cart is attached to the fill adapter on the external service panel. The T-handle on the panel is turned 90°in a clockwise direction. The T-handle is connected to the valve control unit located just behind the service panel. The control unit changes the turning movement of the T-handle to the linear movement of a cable which opens the filler valve. Once the valve is opened, water flows into the fill line for the tank. A flow restrictor in the fill line to the tank makes sure there is no increase in pressure in the tank during the filling process. The tank has a pressure relief valve to prevent overpressure. A check valve in the fill line to the heater prevents any reverse flow from the heater to the storage tank. As the tank fills, the water opens the check valve allowing water to fill the heater vessel. When the tank is approximately 90% full, water flows out the overflow line and drains through the drain mast. The overflow is visible to the servicing crew and indicates that the tank is full. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY The cuffs are either moulded directly to these components or are fastened by bolts. The drain mast and water lines have built in heaters. All the heaters have thermostats which control the temperature in the individual components. The heater system is energized as soon as AC power is connected to the aircraft. This prepares the system for filling by preventing flash freezing of cold water coming into contact with cold components. There is an option for a freeze protection system to be run using external AC power. With this option the wash water and galley water systems do not have to be drained if the aircraft sits for extended periods of time (overnight) in freezing conditions. ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 18 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY WASH WATER SYSTEM SCHEMATIC TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 19 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS WASH WATER SYSTEM OPERATION CONTINUED The system is designed to work to a minimum temperature of -30°C. Below this temperature, the system must be drained. The optional system has an extra relay. When external AC power is connected, the relay is energized using DC power from either the battery bus or from a ground power unit. Once the relay is energized, the aircraft AC bus is bypassed and only the lavatory and galley heaters are energized. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 20 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY WASH WATER SYSTEM LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 21 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS The head of water in the tank forces the water through the check valve into the heater during the filling process. WASH WATER PUMP COMPONENT LOCATION AND DESCRIPTION TANK The water tank gives storage for 27 litres of water and provides the pump with positive head pressure. The tank is installed above the floor, in a compartment under the lavatory sink. It is made from welded stainless steel. On the face of the tank, there is an access hole to allow for cleaning by hand. A cover and gasket is attached with 8 fasteners, sealing the hole. FILL VALVE In the open position, the fill valve allows water to flow from the fill line to the tank. It also allows overflow water from the tank to flow through to the drain mast. In the closed position, the valve isolates the tank from outside ambient pressure. The heated fill valve is a 4 way, 2 position valve. The valve is mechanically operated from the rotary control box located at the ground service panel. Two internal vents in the valve break the vacuum in the fill and overflow lines allowing water trapped within the valve to drain away. HEATING ELEMENT The heating element converts electrical power to warm the valve to prevent freezing. A heating element with a built in thermostat is moulded directly on to the valve body. The heater uses 115V AC variable frequency and the temperature is controlled between 10°C and 30°C. CHECK VALVE The check valve prevents the water in the heater from flowing back into the tank. A check valve is installed in line between the tank and the heater. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY The pump moves water from the tank to the lavatory sink. The pump is a 28V DC geared motor pump, with over-temperature protection. A magnetic clutch connects the motor to the gear drive. At a specified torque, the clutch disconnects and allows the motor to free spin. The over-temperature protection is a self resetting thermostat located in the motor housing. The thermostat switch turns of the electrical power supply if the motor overheats. The pump is protected from freezing by an external heating cuff installed on the pump housing. The pump has an internal bypass valve which prevents the system from over-pressurizing during operation. The bypass valve allows water to re-circulate from the valve outlet back to the inlet. The bypass pressure is set at 38 psi (262 kPa), but is adjustable. DRAIN VALVE The drain valve allows the entire system to be drained to prevent freezing in cold temperatures. The drain valve is a 2 position, 3 way ball valve, mechanically actuated from the rotary control box located at the ground service panel. A heating element is moulded to the top of the valve. A built in thermostat controls the temperature of the heating element between 10°C and 30°C. The heater element uses 115V AC variable frequency power. FILTER The filter removes contamination from the water upstream from the pump. The filter is sintered stainless steel woven wire mesh inside a stainless steel case. It has a nominal rating of 40 microns, 75 microns absolute. This prevents damage to the pump or clogging of other parts of the system. The filter is reusable and can be cleaned by back-flushing or ultrasonic cleaning. The filter is heated by an external heater cuff. ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 22 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY WASH WATER SYSTEM DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 23 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS The thermistor reduces the current to the heater as the temperature increases. WASH WATER COMPONENT LOCATION AND DESCRIPTION CONTINUED HEATER The heater heats water for lavatory warm water washing. The heater is a 1.7 litre stainless steel tank. A 450w heating blanket moulded to the heater supplies heating for the water in the tank. A built in thermostat maintains the water temperature at about 34°C. If the thermostat fails, a thermal fuse will melt and turn off the heater when the water temperature reaches 60°C. This protects the passengers against scalding water. FAUCET The faucet controls the flow of water from the tank into the sink. When the faucet lever is pushed down, a cartridge in the faucet opens and a microswitch is activated. This sends a signal to the five second timer relay to operate the pump. The flowing water holds open the cartridge. When the water stops flowing the cartridge is held in the closed position to prevent water from spilling out during flight manoeuvres. The cartridge self-vents when the system is drained. DRAIN MAST The drain mast drains waste water from the sink while the other line drains the clean water from the system. The drain mast has two drain lines attached to it. A fibreglass/silicon blanket with a built in heater covers the two lines. A similar heater with a thermistor is attached to the drain mast. The two heating circuits are connected in parallel. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 24 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY WASH WATER SYSTEM DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 25 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS WASH WATER COMPONENT LOCATION AND DESCRIPTION CONTINUED GROUND SERVICE PANEL The ground service panel has a fill adapter, a T-handle and a cable control unit. The cable control unit has a control box installed behind the ground service panel with two cables coming out of it. One cable is connected to the fill valve and the other is connected to the drain valve. Rotating the handle causes an inner cog in the control box to engage the cable and move it in or out. This action operates the fill valve connected to the cable and allows the system to be filled with water. Pulling the handle out disengages the inner cog and allows the handle to engage an outer cog. Rotating the handle then operates the drain valve in a similar way. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 26 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - POTABLE WATER SERVICE PANEL DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 27 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS WASH WATER INTERFACES The pump and control relay are powered from the 28V DC R SECONDARY bus, through a 5A circuit breaker. The heaters are powered from the 115V AC VARIABLE FREQUENCY RIGHT BUS through a 10A circuit breaker. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 28 of 48 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 29 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS WASTE SYSTEM GENERAL DESCRIPTION The lavatory waste water system supplies the water for the passenger washroom facilities on board the aircraft. The system also stores the waste water after passenger use and allows it to be removed from the aircraft through a service panel. The toilet unit is an electronically operated, re-circulating flush toilet installed in the lavatory compartment. The lavatory compartment is manufactured in one piece. Any fluids spilled on to the floor are contained within the compartment and then drained overboard through the floor drain. The toilet unit is filled with clean water and is drained of waste water through an exterior service panel. SYSTEM OPERATION The toilet unit has a reservoir tank which holds the fluid used for flushing as well as the waste fluid. The unit also has a motor pump cartridge with a built in filter basket, a timer unit, toilet bowl, flush/fill line with a check valve and a vent line with a muffler. The toilet unit is attached to the lavatory compartment floor by hold down rods and is covered around the base by a decorative shroud. The toilet bowl is made from polished stainless steel and is installed on top of the fluid/waste reservoir. A flush channel allows a flow of fluid to cleanse the bowl during flushing. The unit is drained by dumping fluid and waste into a sewage drain which is directed to a service panel on the exterior of the aircraft. Pushing the flush switch installed on the lavatory wall starts the flush cycle. When the flush switch is pushed, a timer unit installed on top of the toilet unit activates the 28V DC motor driven pump for 5 seconds. The pump causes the flushing fluid to flow through the filter basket to the flush channel at the upper rim of the toilet bowl. The flushing fluid flows down the inner side of the toilet bowl rinsing waste material directly into the reservoir. A one-way hinged flapper valve prevents the waste material and fluid from flowing back into the bowl. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 30 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 31 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS CHECK VALVE WASTE SYSTEM The check valve allows water from the ground cart into the tank for cleaning and refilling, but does not allow water to flow back out through the fill tube. COMPONENT LOCATION AND DESCRIPTION The flush/fill check valve is a mechanical valve installed in the top of the tank assembly. BOWL ASSEMBLY VENT LINE AND MUFFLER The shape of the bowl forces the water and waste flow into the tank. The vent line keeps toilet odours from entering the lavatory compartment while the muffler assembly, installed in the vent line, reduces the noise. The toilet bowl assembly is a polished stainless steel bowl installed on the top of the tank assembly. A flapper valve at the bottom of the bowl prevents waste and water from re-entering the bowl from the tank. TANK ASSEMBLY The tank is vented to the atmosphere through a vent line attached to the top of the tank assembly. The vent line is open to the atmosphere and makes a constant noise while the aircraft is in operation. The muffler assembly is installed in the vent line to reduce the noise. The top has provisions for the installation of the bowl assembly, the motor, pump and filter assembly, the timer, the flush/fill check valve and the vent line elbow. The tank and top assembly are made from fibreglass, with a built in structural reinforcement. PUMP AND FILTER The pump and filter move filtered flush fluid from the tank to the bowl assembly. The motor pump and filter is an electric pump/filter assembly installed in the top of the tank assembly. The filter is a TEF coated basket type filter that sits in the flush fluid. The motor has a built in thermostat which disconnects power when the temperature reaches a preset level. This protects against overheating of the motor if it runs continuously. TIMER ASSEMBLY The timer assembly controls the flush cycle. The timer assembly is an electronic unit that is installed on top of the tank assembly. When the toilet flush timer switch is pushed, the timer unit will operate the pump for 5 seconds. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 32 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY WASTE DISPOSAL LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 33 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY WASTE DISPOSAL DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 34 of 48 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 35 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS WASTE SYSTEM COMPONENT LOCATION AND DESCRIPTION CONTINUED LAVATORY SERVICE PANEL The lavatory waste water system is drained and filled through the lavatory service panel on the exterior of the aircraft. The sewage drain cover is opened and flush/fill cap removed. The coupling connector and flush/fill hoses from the ground cart are connected to the appropriate connectors. The sewage drain plug is removed by operating the plug extractor handle, which is part of the connector. The waste fluid and material drains into the ground service cart. Once the tank has drained, the system is flushed with 10 gallons (37.85 litres) of pressurized water. The water enters the tank through the check valve to the pump inlet and a rotating spray nozzle. The pressurized fluid sprays through the nozzle and cleans the inside of the filter basket and tank sidewalls. Then the drain plug is reinstalled and the unit is filled with 9.5 litres of water and deodorant solution. The drain connector and flush/fill line are then disconnected and the sewage drain cover and flush/fill cap are replaced. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 36 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - LAVATORY SERVICE PANEL DETAIL TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 37 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS WASTE SYSTEM TOILET FLUSH SYSTEM INTERFACES The toilet flush electric motor is powered from the L MAIN bus through a 5A circuit breaker. The electrical connector is attached to the timer unit. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 38 of 48 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 39 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS ANTI-FREEZE PROTECTION SYSTEM GALLEY G1 AND FORWARD LAVATORY INTRODUCTION On aircraft with the anti-freeze protection system for galley G1 and forward lavatory (812CH00003): The anti-freeze protection system lets the aircraft park overnight while the temperature is more than -30°C without the need to drain the water from galley G1 and forward lavatory. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 40 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS ANTI-FREEZE PROTECTION SYSTEM GALLEY G1 AND FORWARD LAVATORY GENERAL DESCRIPTION The anti-freeze protection system has AC heaters in the G1 galley and forward lavatory. A toggle switch on the AC external power receptacle panel is used to energize the heaters and not the remaining electrical systems while AC external power is supplied to the aircraft. The anti-freeze protection system has the components that follow: • • • Toggle Switch, AC GND SERVICE Galley AC Ground Service Power Relay Lavatory AC Ground Service Power Relay TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 41 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS ANTI-FREEZE PROTECTION SYSTEM GALLEY G1 AND FORWARD LAVATORY SYSTEM OPERATION The AC external power A phase is supplied through a lavatory heater circuit breaker and relay to the lavatory heaters and through a galley heater circuit breaker and relay to the galley heaters when the AC GND SERVICE PWR toggle switch is set to the ON position. The DC circuits of the AC external power source is energized by the aircraft battery power bus through the AC GND SERVICE PWR toggle switch. The AC external power source then supplies 28V DC electrical power through a lavatory and galley heaters circuit breaker to energize lavatory and galley relays K1 and K2. When K1 and K2 are energized, the A phase of the AC external power source is supplied to the lavatory and galley heaters. The AC buses in the AC Contactor Boxes (ACCB) are not energized. NOTES: An interlock function lets the ACCBs be energized by an AC external power source without a flight compartment AC power selection. Some AC external power sources do not supply 28V DC power. When the aircraft is connected to such a power source, the battery power bus will energize K1 and K2. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 42 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - ANTI-FREEZE PROTECTION SYSTEM BLOCK DIAGRAM TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 43 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS ANTI-FREEZE PROTECTION SYSTEM GALLEY G1 AND FORWARD LAVATORY COMPONENT LOCATION AND DESCRIPTION AC GND SERVICE TOGGLE SWITCH The AC GND SERVICE toggle switch is used to energize the antifreeze protection system of galley G1 and forward lavatory. The AC GND SERVICE toggle switch is a positive break, two pole, double throw, toggle switch. It has a toggle lever that is connected to a locking mechanism located in the body of the switch. The locking mechanism locks the selection to the set position. The AC GND SERVICE toggle switch is attached to the AC external power receptacle panel with a mounting nut and lock washer. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 44 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - AC GND SERVICE TOGGLE SWITCH LOCATOR TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 45 of 48 BOMBARDIER DHC 8-400 (PWC PW150) POTABLE WATER AND WASTE SYSTEMS ANTI-FREEZE PROTECTION SYSTEM GALLEY G1 AND FORWARD LAVATORY SYSTEM OPERATION The AC GND SERVICE PWR toggle switch is set to the ON position to energize the lavatory and galley heaters and not the remaining aircraft electrical systems. NOTE: There are no indications for this system. TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 46 of 48 BOMBARDIER DHC 8-400 (PWC PW150) WATER/WASTE - ANTI-FREEZE PROTECTION SYSTEM OPERATION TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 47 of 48 BOMBARDIER DHC 8-400 (PWC PW150) INTENTIONALLY LEFT BLANK TO BE USED FOR MAINTENANCE TRAINING PURPOSES ONLY ATA 38 - WATER & WASTE Issue 6 - January 2023 Page 48 of 48