528042 Fisher Paykel Dishwasher Pump Base. Pump Base assembly for DS603 and DD603 Models. Includes seals and o-ring assembly. This is the stator for the pump rotor and fits in the bottom of the drawer. You may wish to also order item #525884P. NOTE! You must transfer the RPS sensor from your existing base over to the new unit. You may wish to order item # 528042B which is a complete pump assembly and includes the base, the rotor, the seals and the RPS sensor.