(1) Fuel inlet. (2) Fuel filter. (3) Fuel outlet. (4) Base. (5) Heater. (6) Temperature sensor. (7) Drain valve.
Some engines may have a combination fuel heater and water separator. The fuel heater is controlled by a thermostat located in the base of the unit. The thermostat is preset to turn the heater ON when the fuel temperature is below 2°C (35°F) and OFF when the fuel temperature is 7°C (45°F).
Water that has been separated from the fuel can be drained from the unit by lifting up on the drain valve (7).