A valve assembly is constructed for use in a filtering system including a
pump and a filter with an inlet and an outlet, for example those systems
used in conjunction with swimming pools. The assembly includes a valve
body with a pump inlet, a filtered output, a waste-water disposal outlet,
a filter inlet, and a filter outlet. Pairs of a plurality of plunger
heads are positioned within the valve body to provide a plurality of
modes of operation, the pairs of plunger heads being positioned within
the valve body in one of a filtering mode, a backwash mode, and a direct
mode in which flow from the pump is directly into the waste-water
disposal outlet. The pairs can be affixed on two different
interchangeable plungers or moveably positioned on a single plunger.