Land Rover Discovery: Fuel Fired Booster Heater - Fuel Pump

1. Fuel line connector
2. Non return valve
3. Solenoid coil
4. Plunger
5. Filter insert
6. Fuel line connector
7. O-ring seal
8. Spring
9. Piston
10. Bush

The Fuel Fired Booster Heater (FFBH), fuel pump is mounted adjacent to the fuel tank and regulates the fuel supply to the FFBH. The pump is a selfpriming, solenoid operated plunger pump, controlled by a Pulse Width Modulation (PWM) signal from the control module in the FFBH. When the pump is de-energized, it provides a positive shut-off of the fuel supply.

The solenoid coil of the fuel pump is installed around a housing which contains a plunger and piston. The piston locates in a bush, and a spring is installed on the piston between the bush and the plunger. A filter insert and a fuel line connector are installed in the inlet end of the housing. A nonreturn valve and a fuel-line connector are installed in the fuel outlet end of the housing.

While the solenoid coil is de-energized, the spring holds the piston and plunger in the closed position at the inlet end of the housing. An O-ring seal on the plunger provides a fuel tight seal between the plunger and the filter insert, preventing any flow through the pump. When the solenoid coil is energized, the piston and plunger move towards the outlet end of the housing, until the plunger contacts the bush; fuel is then drawn in through the inlet connection and filter. The initial movement of the piston also closes transverse drillings in the bush and isolates the pumping chamber at the outlet end of the housing. Subsequent movement of the piston then forces fuel from the pumping chamber through the non-return valve and into the line to the fuel fired booster heater. When the solenoid de-energizes, the spring moves the piston and plunger back towards the closed position. As the piston and plunger move towards the closed position, fuel flows past the plunger and through the annular gaps and transverse holes in the bush to replenish the pumping chamber.

Fuel fired booster heater

The Fuel Fired Booster Heater (FFBH) is installed in the coolant supply line to the climate control assembly and is located behind the front-right fender.

One electrical connector connects the FFBH to the vehicle wiring.

The FFBH comprises the following:

• Combustion air fan
• Burner housing
• Heat exchanger
• Air inlet hose and muffler
• Exhaust pipe and muffler
• Control module.

Auxiliary Climate Control Fuel Fired Booster HeaterSectioned View of Typical Fuel Fired Booster Heater

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