10 x Wisa Sphinx Side Entry Cistern Fill Valve Diaphragm Washer — 8050800311
This genuine Wisa Sphinx 8050800311 commercial bulk pack contains ten factory-original replacement rubber float valve membranes, engineered specifically for original Wisa side-entry and universal inlet fill valves. When a toilet cistern continuously runs into the pan, trickles constantly, or fills up with a loud whistling noise, a split or perished internal diaphragm is the primary culprit. Swapping out the degraded washer with one of these authentic components quickly restores a silent, reliable water shut-off while providing an inventory of original parts for multi-property maintenance, commercial facilities, or high-volume plumbing trade use.
Identification Guide:
MPN: 8050800311 (Alt: 8050.800311) | Pack Quantity: 10 x Washers | Diameter: 29mm | Total Height: 20mm (base to cone tip)
Key Features
- Precision Moulding: Equipped with a built-in hard plastic support plate to guarantee structural strength under high fluid pressures.
- Wisa Specific Fit: Tailored exclusively to the internal profile of Wisa fill valves; will not seal correctly in other standard universal brands like Siamp.
- High Elastomer Memory: Crafted from chloramine-resistant rubber compounds designed to combat chemical deterioration from water treatments.
- Wholesale Trade Pack: Provides ten identical, original manufacturer spares to keep multi-property systems running efficiently while maximizing cost savings per unit.
Installation Note
Isolate the water supply before attempting installation. Carefully unscrew the circular retaining cap located on the side entry inlet valve body, remove the old membrane, and clean any collected sand, grit, or limescale away from the valve seat. Insert one of the new 8050800311 washers firmly in place, ensuring the plastic cone points into the guide, and hand-tighten the retention cover firmly to secure.



