Pentair Waterfall/Challenger Pump Diffuser O-Ring, 355331Z In stock$754
Quick overview
- Genuine Pentair The factory o-ring 355331Z, sized to the original.
- Diffuser seal Seats between the diffuser and the housing so water is forced through the impeller instead of around it.
- Waterfall and Challenger Listed by Pentair for both pump families under one part number.
- A weak flow clue A flattened or cracked diffuser o-ring lets water bypass the impeller, which reads as poor flow with a healthy motor.
- Do it with the pump already open The diffuser comes off for most shaft seal and impeller work, so this is cheap insurance while you are in there.
- Lubricate on assembly A silicone based o-ring lubricant helps it seat without rolling or pinching.
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Product details
The Pentair 355331Z is the diffuser o-ring for the Waterfall and Challenger pumps. It is the genuine Pentair part, cut and sized to the original.
What the diffuser o-ring does
The diffuser sits over the impeller and turns the impeller output into usable pressure. For that to work, the diffuser has to be sealed against the housing so that water is driven through it rather than allowed to slip back around the outside. The o-ring is the piece that makes that seal. It is small, it is inexpensive, and when it goes flat or cracks the pump quietly loses flow with no obvious cause. Owners usually chase the basket, the skimmer and the impeller first.
When to change it
Any time the pump is open. The diffuser comes off for shaft seal replacement, impeller changes and blockage clearing, and the o-ring is disturbed every time. A compressed o-ring that has taken the shape of its groove will not reliably reseal once it has been moved, so it is worth replacing rather than reusing. Seat it clean, use a silicone based o-ring lubricant, and check it has not rolled in the groove before the diffuser goes back down.
| Brand | Pentair |
|---|---|
| Manufacturer part number | 355331Z |
| UPC | 788379885687 |
| Type | Diffuser o-ring |
| Fits | Pentair Waterfall and Challenger pumps |
| Shipping weight | 0.02 lb |
| Ships | Parcel |
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