Valve Cover O-Ring for Aqua UV Ultima II Filters, 1.5" Valve
The valve cover O-ring on an Ultima II filter creates the watertight seal between the multi-port valve cover and the filter housing. When this seal fails, water seeps around the valve cover during normal operation and backwash. This OEM Aqua UV replacement fits the 1.5" valve cover assembly on Ultima II series pond filters and restores a complete seal.
Why O-Rings Fail
Constant UV exposure, seasonal temperature swings, and ozone from pond water degrade rubber over time. The O-ring hardens, loses its ability to compress and spring back, and eventually cracks or shrinks enough to let water past. In most Ultima II systems, inspecting all O-ring points annually prevents mid-season leaks.
| Specification | Value |
|---|---|
| Part Number | A50063 |
| Valve Size | 1.5" (1-1/2") |
| Location | Valve cover assembly |
| Material | High-grade elastomer, UV and ozone resistant |
| Compatibility | Aqua UV Ultima II series pond filters |
Installation
Shut down the filter and release system pressure. Remove the valve cover bolts and lift the cover away from the housing. Peel out the old O-ring and clean the groove and mating surface thoroughly. Apply a thin coat of silicone grease to the new O-ring and press it into the groove. Reinstall the valve cover, tighten bolts evenly, and restart the system. Check the seal during the first backwash cycle for any weeping.
Keep a spare on hand for annual filter maintenance. Replacing this O-ring proactively at spring startup costs less than the water loss from a slow season-long leak.

