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817-4050 spa filter equivalents
Part number 817-4050 appears in 1 cross-reference row below. Each row lists the OEM, Unicel and Pleatco numbers that the source documents treat as interchangeable, plus the cartridge size so you can confirm against your old filter.
The same numbers, on one page, are in the cross-reference lookup. A schedule for this part number, and the buy link, are on the replacement schedule and reorder page. Published intervals by brand are in the replace and clean calculator.
Waterway Plastics 4CH-949 cartridge (OEM 817-4050), 4-15/16" (125 mm) × 13-1/2" (343 mm), 50 sq ft. Unicel 4CH-949, Pleatco PWW50L.
Unicel 4CH-949
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| OEM | 817-4050 |
|---|---|
| Unicel | 4CH-949 |
| Pleatco | PWW50L |
| Filbur | FC-0172 |
| Size | 4-15/16" (125 mm) × 13-1/2" (343 mm), 50 sq ft |
Sources
- Unicel 2026 Replacement Guide: Waterway list PDF p.64: 817-4050 = 4CH-949, Teleweir, 4-15/16" x 13-1/2", 50 sq ft. Spec table PDF p.9: 210 pleats, 2" female SAE, standpipe note. (PDF)
- Waterway Plastics Service Logic cartridge table: Fetched 2026-11-09: 817-4050, 50 sq ft, 4-15/16" x 13-1/2", SAE thread (web page)
- Pleatco 2023 Catalog: Spec table PDF p.32: PWW50L, OEM 817-4050. Cross-reference PDF p.47: 4CH-949 = PWW50L. (PDF)
- Filbur Catalog & Reference Guide: FC-0172 in the Rising Dragon section: 4CH-949, 4-15/16" x 13-1/2", 2" female SAE, 50 sq ft (PDF)
Not in sources: Outside diameter 4-15/16" vs Pleatco 5". Length 13-1/2" vs Pleatco 13-3/16". Female thread 2" (Unicel, Filbur) vs 1-1/2" (Pleatco). Filbur's 4CH-949 row does not print 817-4050..
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