Pentair Shaft Seal U109-433SS – Centrifugal Pump Replacement Seal for Pool & Spa Pumps
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The Pentair U109‑433SS Shaft Seal is a genuine OEM replacement part engineered to restore and maintain proper sealing in centrifugal pool and spa pumps. Shaft seals are critical components that prevent water from entering the motor housing while allowing the pump shaft to rotate smoothly—protecting internal components and preserving efficient pump operation.
This replacement seal features corrosion‑resistant stainless steel and durable elastomer sealing surfaces to withstand the harsh chemical and environmental conditions typical of pool and spa equipment. Whether you’re repairing a leak or performing routine maintenance, the U109‑433SS delivers dependable performance and helps extend the life of your pump.
Pentair U109‑433SS Shaft Seal Compatibility
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Designed for centrifugal pool and spa pumps that require Pentair seal U109‑433SS
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Compatible with many Pentair pump models and mechanical seal housings
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Suitable for residential and commercial pool and spa systems
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Works in applications where the original shaft seal has worn, cracked, or failed
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Fits standard mechanical seal mounts on compatible centrifugal pump assemblies
Frequently asked questions
How do I know which O-ring or gasket size I need?
Seals are specified by inside diameter and cross-section thickness, not by the equipment they sit in. Measure the old seal, or use the part number from your equipment's parts diagram, since visually similar rings are frequently a size apart.
What is the part number for this seal?
Pentair lists this seal under part number U109-433SS. Quote U109-433SS when you cross-reference against your equipment manual, an existing part, or a parts diagram, so you are comparing the same revision.
Should I lubricate the seal on installation?
Yes - a thin film of silicone-based pool lubricant helps the seal seat evenly and makes the next service far easier. Do not use petroleum-based grease, which swells and degrades most elastomers used in pool equipment.
How do I confirm this fits my equipment?
Match the part number stamped on the component you are replacing, or look it up in the parts list for your Pentair equipment. If your model or serial number is not named on this page, send it to us before you order and we will confirm the fit.
How often do pool seals need replacing?
Seals are consumables. Replace them whenever the component is opened, and sooner if you see flattening, cracking, a chalky surface or any weeping. A failed seal on the suction side draws air and can make a pump lose prime.
Is there a warranty on this seal?
It carries the standard Pentair manufacturer warranty. The terms are set by Pentair, and on some equipment the coverage only applies when a licensed professional performs the installation. Keep the receipt and packaging until you have confirmed correct operation.