Maytronics Dolphin Supreme M5 impeller cylinder with screws assembly - 9991044-ASSY

Maytronics Dolphin Supreme M5 impeller cylinder with screws assembly

This is the OEM impeller cylinder assembly for the Dolphin Supreme M5, supplied complete with its retaining screws. The cylinder houses the impeller blade and channels water flow through the filtration circuit; without an intact cylinder, the robot loses suction and cleaning performance drops immediately.

What this impeller cylinder does in the Dolphin

The impeller cylinder forms the sealed water-flow chamber around the spinning impeller. It directs pool water from the intake port, past the impeller blade, and towards the filter basket. Any crack, split, or deformed seating surface in the cylinder breaks this pressure circuit and causes the robot to under-draw water, leaving debris on the pool floor.

Which Dolphin models it fits

This assembly is confirmed for the Dolphin Supreme M4, Supreme M5, Nautilus Plus, C3, C3 CB, C4 CB, M200, M400, and Triton Plus. Always cross-reference your robot’s parts schematic before ordering — the impeller cover (9991045-ASSY) is a separate item and not included here.

Signs it needs replacing

Visible hairline cracks along the cylinder wall are the clearest indicator. You’ll also notice a marked drop in suction at the intake port, or hear the impeller motor running louder than usual as it works against a loss of back-pressure. Discoloration, warping from prolonged UV or chemical exposure, or stripped screw threads in the cylinder body all justify replacement.

How to install it

Remove the impeller cover assembly first, then unscrew the cylinder using the supplied screws as a guide for thread size. Seat the new cylinder flush against the motor housing, ensuring the screw bosses align before tightening evenly in a cross pattern to avoid distorting the plastic. Refit the impeller cover and test suction at the intake before returning the robot to the pool.