Circuit Description

The fuel manager/filter assembly consists of fuel heater, water-in-fuel sensor, and a filter. Filter contains coalescer (the device that combines small droplets of water into larger ones) and filter/separator. A fuel lift pump delivers diesel fuel from tank to fuel filter. As fuel enters filter, fuel passes first through fuel heater. Heater contains a thermostatic switch that opens or closes to turn heater OFF or ON, depending on temperature of fuel. Fuel then passes through filter and water coalescer, where droplets of water-in-fuel combine into larger drops that fall into water reservoir in filter. When fuel flows from fuel manager/filter assembly to injection pump, fuel is clean and free of water. Fuel heater is operated by a built-in thermostatic switch. Thermostatic switch completes circuit for fuel heater element when a temperature below 46°F (8°C) is detected.