
Pentair O-Ring, 2-357, 357255
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Quick overview
- Genuine Pentair The factory o-ring, part number 357255.
- Size 2-357 The standard size designation, which is how the ring is identified across parts lists.
- SuperFlo lid Listed as the lid o-ring for Pentair SuperFlo pool pumps.
- Also cataloged elsewhere It appears with Pentair OptiFlo and Sta-Rite SuperMax pump parts as well.
- A prime problem in disguise A pump that loses prime or holds air in the pot very often has a tired lid o-ring behind it.
- Silicone lubricant only Use a pool rated silicone lubricant on the ring, not a petroleum grease.
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Frequently bought together

O-Ring, 2-357, 357255
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Product details
The Pentair 357255 is the genuine lid o-ring, size 2-357, for SuperFlo pool pumps. Pentair also lists it with OptiFlo and Sta-Rite SuperMax pump parts.
The o-ring that causes prime problems
The lid o-ring seals the strainer pot against atmosphere while the pump pulls a vacuum on it. Once the ring hardens, flattens or picks up a nick, air gets in past it, and the pump either refuses to prime or runs with a pocket of air trapped under the clear lid. It looks like a suction line problem and it usually is not.
Fitting and care
Clean the groove and the lid seat before the new ring goes on, and use a silicone lubricant intended for pool equipment. Petroleum grease will swell and break down the rubber. Do not overtighten the lid to make a worn o-ring seal, since that distorts the ring and the lid without solving anything.
| Brand | Pentair |
|---|---|
| Manufacturer part number | 357255 |
| UPC | 788379688509 |
| Type | Lid o-ring |
| Size | 2-357 |
| Fits | Pentair SuperFlo pumps |
| Also cataloged with | Pentair OptiFlo, Sta-Rite SuperMax pump parts |
| Part type | Pool pump part |
| Shipping weight | 0.05 lb |
| Ships | Parcel |
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Questions and answers
What people ask about this product, answered by our pool techs.
Which pump is this for?
What does 2-357 mean?
My pump keeps losing prime. Is this the fix?
What lubricant should I use?
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