Waterway Plastics OEM 817-4050 spa filter (4CH-949)

Teleweir

Replacement numbers

Unicel 4CH-949, Pleatco PWW50L

Fits Waterway Plastics OEM 817-4050.

Diameter 4-15/16" (125 mm)Length 13-1/2" (343 mm)50 sq ft

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Unicel4CH-949
PleatcoPWW50L (Spec table PDF p.32: PWW50L, 5" x 13-3/16", 1-1/2" female SAE, 50 sq ft, OEM 817-4050. Cross-reference PDF p.47: 4CH-949 = PWW50L.)
FilburFC-0172
Topv-groove handle
Bottom2" female SAE
Ø 4-15/16" (125 mm)13-1/2" (343 mm)Side view · end views belowTopBottom
Top: v-groove handle
Bottom: 2" female SAE
Drawn to scale from the listed diameter and length. Handles, threads and closed ends are drawn as symbols, not to scale. 50 sq ft media.

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For Waterway Plastics, 4CH-949 cartridge (OEM 817-4050) sits in Teleweir. The cross-reference prints OEM 817-4050; Unicel 4CH-949; Pleatco PWW50L; Filbur FC-0172. 4-15/16" across, 13-1/2" long, top v-groove handle, bottom 2" female SAE, 50 sq ft.

Catalog note for 817-4050: Teleweir 50. Same 13-1/2" length as 817-4025. Unicel and Waterway's table: 4-15/16" x 13-1/2", 50 sq ft, 2" female SAE, 210 pleats, for a 1-1/2" male SAE standpipe. Pleatco PWW50L is 5" x 13-3/16", 1-1/2" female SAE, 50 sq ft, OEM 817-4050. Filbur FC-0172 matches Unicel's length and 2" female SAE and 50 sq ft, in the Rising Dragon section, and that row does not print 817-4050.

4CH-949 (OEM 817-4050), Pleatco side: Spec table PDF p.32: PWW50L, 5" x 13-3/16", 1-1/2" female SAE, 50 sq ft, OEM 817-4050. Cross-reference PDF p.47: 4CH-949 = PWW50L..

817-4050, Filbur note: Rising Dragon section: FC-0172, 4-15/16" x 13-1/2", 2" female SAE, 4CH-949, 50 sq ft. OEM cell does not print 817-4050..

4CH-949 is easy to confuse on the Waterway Plastics table. 4CH-926 differs by Unicel 4CH-926, Pleatco PWW25L, Filbur FC-0168, 25 sq ft, OEM 817-4025, note says Teleweir 25. Unicel and Waterway's table agree: 4-15/16" x 13-1/2", 25 sq ft, SAE thread. Unicel's spec table says 2" female SAE, 105 pleats, for a 1-1/2" male SAE standpipe (the standpipe note is printed on the 4CH-935 and 4CH-949 spec lines). Pleatco PWW25L is 5" x 13-3/16", 1-1/2" female SAE, 25 sq ft, and that spec line does not print 817-4025. The cross-reference does: 4CH-926 = PWW25L. Filbur FC-0168 is 13-1/16" long and 1-1/2" female SAE. Same length as 817-4050, half the area.. C-4326 differs by Unicel C-4326, Pleatco PRB25-IN, Filbur FC-2375, 13-5/16" long, top 2-1/8" open, bottom 2-1/8" open, 25 sq ft, OEM 817-2500, note says 25 sq ft open top-load. Unicel: 4-15/16" x 13-5/16", open 2-1/8", 106 pleats, 25 sq ft. Pleatco PRB25-IN lists OEM 817-2500 at 5" outside diameter and the same length. Filbur prints this OEM on two rows: FC-2375 at 13-5/16" (PRB25-IN, C-4326) and FC-2910, which the size table lengths at 13-1/4" and the Waterway section lengths at 12-1/4", with no Pleatco number. The size stored here is Unicel's. The 50 sq ft cartridge of the same length is 817-5000..

Left blank on purpose: 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..

Where those figures are printed: Unicel 2026 Replacement Guide on 4CH-949 (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.). Waterway Plastics Service Logic cartridge table on 4CH-949 (Fetched 2026-11-09: 817-4050, 50 sq ft, 4-15/16" x 13-1/2", SAE thread). Pleatco 2023 Catalog on 4CH-949 (Spec table PDF p.32: PWW50L, OEM 817-4050. Cross-reference PDF p.47: 4CH-949 = PWW50L.). Filbur Catalog & Reference Guide on 4CH-949 (FC-0172 in the Rising Dragon section: 4CH-949, 4-15/16" x 13-1/2", 2" female SAE, 50 sq ft).

If you know the Waterway Plastics model and not the part number, use the Waterway Plastics filter by model and year lookup.

Check the cartridge you removed

Measure diameter, length, and both ends, then compare them with the figures above. The steps are in the measuring guide. Why the bottom decides whether it seals: open-end vs threaded filters. Power, the retainer, and not running the spa empty: how to install a cartridge. Number formats: how Filbur, Unicel and Pleatco numbers compare.

The same 4CH-949 number is also on the Master Spas, PDC Spas pages.

Other Waterway Plastics cartridges

All 12 Waterway Plastics spa filters

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Sources

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..