Pentair Rainbow 3" Cap O-Ring | R172009Z

Pentair Rainbow O-Ring, Cap & Extension | Model 300 Series Automatic Feeder | R172009Z

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SKU:
R172009Z
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About This Item

The Pentair Rainbow O-Ring (R172009Z) is the OEM replacement cap and extension O-ring for the Rainbow Model 300 Series Automatic Chemical Feeders, including the 300-29X Commercial Size Feeder, the 320 In-Line Automatic Feeder, and Rainbow 10" and 20" Extension assemblies.

IMPORTANT: LUBRICATION REQUIRED — SOLD SEPARATELY
Always lubricate this O-ring with a silicone-based lubricant before installation. We carry the Pentair R172351 Lifeguard Silicone Lubricant — the OEM-matched product for Pentair equipment.

This O-ring seals the cap or extension joint on Rainbow automatic chemical feeders. A failed or degraded O-ring at this connection point allows chlorine or bromine to bypass the seal, leading to chemical leaks and loss of proper feeder pressure. Replacing this O-ring restores a watertight seal at the cap or extension assembly.

Specifications

Pentair Part Number R172009Z
Part Name O-Ring, Cap / Extension
Part Category O-Rings
Quantity Included 1 (Each)
Compatible Equipment Rainbow Model 300 Series Automatic Feeders; Rainbow 10" & 20" Extensions
Brand / Legacy Brand Pentair (formerly Rainbow)

Fits Into

Brand Equipment Line Model / Part Number Notes
Pentair (formerly Rainbow) Model 300, 302, 300-19, 300-29 Series 300
Pentair (formerly Rainbow) Model 300, 302, 300-19, 300-29 Series 302
Pentair (formerly Rainbow) Model 300, 302, 300-19, 300-29 Series 300-19
Pentair (formerly Rainbow) Model 300, 302, 300-19, 300-29 Series 300-29
Pentair (formerly Rainbow) Sanitizer & Water Quality 300-29X O-ring, cap
Pentair (formerly Rainbow) Sanitizer & Water Quality 320 O-ring, cap
Pentair (formerly Rainbow) Extensions / Dispensers / Flow Indicators R172087 O-ring for extension complete models (10 in. Extension Complete)
Pentair (formerly Rainbow) Extensions / Dispensers / Flow Indicators R172283 O-ring for extension complete models (20 in. Extension Complete)

Compatibility is based on Pentair parts documentation and available OEM records. This is not an exhaustive list. For certainty, verify the part number in your equipment's manual or on the original part itself before ordering.

Poolaroo Pro Tip

Before threading the cap or extension back onto your Rainbow feeder, apply a thin, even coat of silicone-based lubricant to this O-ring. Silicone lubricant keeps the O-ring pliable and prevents the twisting and micro-tearing that causes early seal failure. The Pentair R172351 Lifeguard Silicone Lubricant is the OEM-matched option for Rainbow equipment. Never use petroleum-based lubricants — they degrade rubber O-rings rapidly and will shorten the life of this seal.

CALIFORNIA PROPOSITION 65 WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.
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Pentair Pool Products and Parts

About Pentair Pool Products and Parts

Pentair is often considered the "gold standard" for pool professionals, and for good reason. Founded in 1966 (originally by five inventors making high-altitude balloons!), the company has evolved into the global leader in smart, sustainable water solutions. For the DIY homeowner, Pentair represents the intersection of rugged durability and silicon valley-tier technology. They pioneered the Variable Speed Pump revolution with the IntelliFlo®, saving American pool owners millions in energy costs. Today, their ecosystem focuses heavily on automation, allowing you to control your pump, heater, lights, and chemistry from a single app. While they are a favorite among professional builders, their "EC" (E-Commerce) line of equipment allows homeowners to access pro-grade technology with valid warranties for DIY installation.

Why We Trust Pentair Pool Products and Parts
Energy Efficiency Leaders: Recipient of the ENERGY STAR® Partner of the Year award for over a decade; their pumps are designed to pay for themselves in energy savings.

Smart Automation: The Pentair Home App and IntelliCenter systems offer best-in-class control over your pool ecosystem from anywhere in the world.

Professional Pedigree: The brand most often recommended and installed by pool builders for high-end residential pools.

Eco-Conscious: Dedicated to reducing water waste and energy consumption through "Green" technology innovations.

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