Description
The Pentair Skimmer Extension Collar (WC37-503P) is the OEM replacement collar for the Pentair U-3 Skimmer series, designed specifically for vinyl liner pool installations.
The extension collar raises the skimmer body to the correct height relative to the vinyl liner surface, ensuring the weir door operates at the proper water level and the skimmer face plate seats flush against the liner. When the collar is cracked, warped, or missing, the skimmer throat can sit out of alignment with the liner compromising the seal and reducing surface skimming performance. Replacing it with the correct OEM part restores the proper geometry of the assembly.
Specifications
| Pentair Part Number | WC37-503P |
| Part Name | Skimmer Extension Collar |
| Application | Vinyl liner pools only |
| Quantity Included | 1 (Each) |
Fits Into
| Brand | Equipment Line | Model / Part Number | Notes |
| Pentair | U-3 Skimmer | 09655-2403 | For use on Vinyl Liner Skimmers. Verify fitment before ordering. |
| Pentair | U-3 Skimmer | 09655-2404 | For use on Vinyl Liner Skimmers. Verify fitment before ordering. |
| Pentair | U-3 Skimmer | 09655-1403 | For use on Vinyl Liner Skimmers. Verify fitment before ordering. |
| Pentair | U-3 Skimmer | 09655-1404 | For use on Vinyl Liner Skimmers. Verify fitment before ordering. |
Compatibility is based on Pentair parts documentation and available OEM records. This is not an exhaustive list. For certainty, verify the part number in your equipment’s manual or on the original part itself before ordering.
Pro Tip
This collar is specified for vinyl liner installations only it is not the correct component for concrete or fiberglass skimmer applications. Before ordering, locate the model number stamped on the inside of your skimmer body and confirm it matches one of the U-3 series models listed above. If your U-3 skimmer is showing signs of liner pull or weir door misalignment, inspect the collar for stress cracks along the mounting flange that is the most common failure point on this component.
