Abstract: An apparatus for conditioning fluid. In one embodiment of the present invention, there is an apparatus which comprises two filters and an electrically actuatable switching valve. Fluid provided to the apparatus may be routed to either filter by the switching valve. A controller positions the valve to provide fluid to a particular filter based on a measurement of pressure downstream of the filter, provided that the temperature of the fluid is above a predetermined level. Further, the invention includes proximity switches by which the controller can determine the coupling or uncoupling of a filter from the body. Various fuel heaters are provided for heating the fuel.

Abstract: A fuel filter constructed and arranged with a heater and designed for fuel-water separation includes a unitary housing (casting) which has an open top to be closed by a threaded lid and a closed base which in combination with a surrounding sidewall defines an interior space. A fuel filter cartridge including a filter element, centertube, and top and bottom endplates is disposed in the interior space such that there is a water collection space between the bottom endplate and the closed base of the housing. The lid includes a plurality of snap-fit fingers arranged in an annular array for press-on attachment to the top endplate. A heater ring is provided within the housing and is positioned around the filter cartridge. The heater ring provides both a flow path for entering fuel and a plurality of positive-temperature-coefficient stones which assist in the heating of the fuel. Control of the heater ring is provided by a heater connector and thermostat combination.