Pentair - UltraFlow Plus prefilter housing - R39017102

Pentair UltraFlow Plus prefilter housing

This is the prefilter housing — the strainer pot body — for the Pentair UltraFlow Plus pool pump. It is the moulded chamber that sits at the front of the hydraulic assembly, houses the strainer basket, and channels pool water through to the impeller. Without an intact housing, the pump cannot maintain the sealed, pressurised flow path it needs to operate correctly.

What this prefilter housing does in the UltraFlow Plus

The housing holds the strainer basket in position and forms the sealed wet end chamber through which all pool water passes before reaching the impeller. It takes the full hydraulic load of the pump in operation and must remain crack-free and correctly seated to prevent air ingestion and flow loss. The bayonet-style cover locks directly onto this housing, so any distortion or damage to the housing threads or seating surface will compromise the seal even with a new lid.

Which UltraFlow Plus models it fits

This housing is confirmed to fit the Pentair UltraFlow Plus pump range across the following model codes: P-UFL-071, P-UFL-073, P-UFL-101, P-UFL-103, P-UFL-151, P-UFL-153, P-UFL-201, P-UFL-203, P-UFL-301, and P-UFL-303. That spans the full output range from 0.55 kW entry-level units up to 2.2 kW commercial-duty variants. Check your pump’s model label before ordering — the housing is not shared with the standard UltraFlow (non-Plus) range.

Signs it needs replacing

Visible cracks or stress-whitening on the body are the clearest indicators — even a hairline fracture will admit air and cause the pump to lose prime. If you notice the pump running noisily, surging, or failing to prime despite a good basket seal and correct water level, inspect the housing body carefully under load. Distortion around the cover seating ring — often caused by overtightening or thermal cycling — will also prevent a reliable seal regardless of gasket condition.

How to install it

Shut down the pump and isolate the circuit before starting. Disconnect the inlet and outlet pipe unions, release the clamp band that joins the motor-drive section to the wet end, and pull the old housing clear. Transfer the strainer basket to the new housing, refit the clamp band, and reconnect the pipe unions. Torque the unions by hand and a quarter-turn — no tools needed on the unions themselves. Refill and bleed air before restarting. Total time is typically under 20 minutes with basic plumbing tools.