Fuel Fired Booster Heater
Diesel Vehicles
| ITEM | DESCRIPTION |
|---|---|
| 1 | Electrical connector |
| 2 | Coolant outlet |
| 3 | Support bracket |
| 4 | Exhaust outlet |
| 5 | Air intake hose (a canister type acoustic muffler is incorporated into the air intake hose) |
| 6 | Coolant pump inlet |
| 7 | Coolant pump |
| 8 | Fuel inlet |
| 9 | Bleed screw |
| 10 | Coolant inlet hose |
| 11 | Coolant tube connector/FFBH coolant changeover valve bracket |
| 12 | Fuel fired booster heater base unit |
| 13 | Exhaust flexible section |
| 14 | Muffler |
| 15 | Exhaust tailpipe bush |
| 16 | Muffler bracket |
| 17 | Exhaust bracket |
Petrol Vehicles (non NAS)
| ITEM | DESCRIPTION |
|---|---|
| 1 | Electrical connector |
| 2 | Coolant outlet |
| 3 | Support bracket |
| 4 | Exhaust outlet |
| 5 | Air intake hose |
| 6 | Coolant pump inlet |
| 7 | Coolant pump |
| 8 | Fuel inlet |
| 9 | Bleed screw |
| 10 | Coolant inlet hose |
| 11 | Coolant tube connector/FFBH coolant changeover valve bracket |
| 12 | Fuel fired booster heater base unit |
| 13 | Exhaust flexible section |
| 14 | Muffler |
| 15 | Exhaust tailpipe bush |
| 16 | Muffler bracket |
| 17 | Exhaust bracket |
| 18 | Charcoal canister (where fitted) |
The Fuel Fired Booster Heater (FFBH) is installed in the engine compartment, on a support bracket attached to the rear of the right suspension housing. It is connected in series with the coolant supply to the climate control assembly. A flying lead on the FFBH connects it to the vehicle wiring. The FFBH consists of the following:
- A Fuel Fired Booster Heater Control Module (FFBHCM)
- A combustion air fan
- A combustion chamber
- A heat exchanger
- A coolant pump
- An air intake hose and muffler
- An exhaust pipe and muffler.
Fuel Fired Booster Heater Control Module
The Fuel Fired Booster Heater Control Module (FFBHCM) controls and monitors operation of the Fuel Fired Booster Heater (FFBH) system. Power for the FFBHCM is provided by a permanent feed from the QCCM (Quiescent Current Control Module) integrated in the RJB (Rear Junction Box). A Local Interconnect Network (LIN) bus connection provides the communication link between the FFBHCM and the ATCM (Automatic Temperature Control Module). The FFBHCM also has:
- A ground connection
- Power feed and ground connections with the FFBH coolant pump
- A power feed connection with the FFBH fuel pump
- A signal line connection with the FFBH receiver (vehicles with timed climate control only).
Combustion Air Fan
The combustion air fan regulates the flow of air to the heater so as to ensure correct combustion. If the heater is operational while the engine is stopped or the heater enters the control idle phase, the air fan will continue to run in order to cool the combustion chamber in readiness for the next required start. The operation of the fan may be noticed during this process. This is perfectly normal.
Combustion Chamber
The combustion chamber is located in the heat exchanger casing and the combustion air fan casing. The fuel feed pipe of the combustion chamber extends up through the cover of the combustion air fan. A glow plug is installed in the combustion chamber to provide the ignition source for the fuel:air mixture.
Heat Exchanger
The heat exchanger transfers heat generated by the combustion chamber to the engine coolant. An overheating temperature sensor and a surface temperature sensor are installed in the heat exchanger and connected to the Fuel Fired Booster Heater Control Module (FFBHCM). The FFBHCM uses the temperature inputs to control system operation.
Fuel Fired Booster Heater Coolant Pump
The Fuel Fired Booster Heater (FFBH) coolant pump is an electric pump attached to outboard end of the FFBH support bracket. The pump intake is connected to either the heater coolant feed from the engine (vehicles without timed climate control) or to the FFBH coolant changeover valve (vehicles with timed climate control). A hose, which incorporates a bleed screw, connects the outlet of the coolant pump to the coolant inlet of the FFBH.
The coolant pump runs continuously while the FFBH is in control idle or active operating modes. While the FFBH is inactive, coolant flow is reliant on the engine coolant pump.
Air Intake Hose and Muffler
A canister type muffler and filter is incorporated into the air intake hose.
Air Intake Hose and Charcoal Canister
Depending on specification some petrol vehicles are fitted with an extended air-intake hose and activated charcoal canister.
Exhaust Pipe and Muffler
The exhaust pipe and muffler directs exhaust combustion gases to atmosphere below the vehicle, to the rear of the right front wheel arch and towards the center of the vehicle. Exhaust vapor may be visible when the Fuel Fired Booster Heater (FFBH) is running, depending on atmospheric conditions. Under normal operating conditions, the exhaust vapor will subside once the FFBH has achieved "Power status" and the exhaust pipe has reached normal operating temperature.
Under certain circumstances, for example after heater replacement or the disconnection of the fuel or coolant circuits, smoke may be visible from the general vicinity of the heater rather than the outlet of the exhaust. This may be as a result of residual fuel or coolant on the exhaust or heater body as a result of the service procedure. Under these circumstances, the heater must be run continually for 15-20 minutes until there are no signs of excessive smoke.