Description

Adapter is a precision-molded reducer that converts a 4-inch threaded opening on an FRP (Fiberglass Reinforced Plastic) pressure vessel to a 2.5-inch threaded port. It provides a secure, leak-free connection for standard 2.5″ filtration control valves, making it ideal for water softeners, filtration tanks, and reverse osmosis systems.

This adapter is perfect for new installations or retrofitting existing FRP tanks, allowing larger vessels to accommodate smaller, standard control valves without compromising performance.

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Key Features

• Converts 4″ FRP vessel threads to 2.5″

• Enables installation of 2.5″ control valves on larger vessels

• Durable, corrosion-resistant engineering plastic

• Quick and easy installation with standard threading

• Ideal for both new setups and retrofits

• Typical 4″ → 2.5″ Adaptor Sizes (in mm) 🔵 4″ Side (Outer Thread) Major diameter: 113–116 mm Thread type: BSPP or BSPT (depending on supplier) 🔵 2.5″ Side (Inner Thread) Major diameter: 75–78 mm Thread type: BSPP usually Depth: 18–25 mm 🔵 Height 35–50 mm 🔵 Material PP (Polypropylene) ABS Nylon (strongest) 🔵 O-ring Most 4″ adaptors use: 90–95 mm ID O-ring 5–7 mm cross-section -ADPT-4-2

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Applications

• Water softeners

• Sand, carbon, or multimedia filtration systems

• Reverse osmosis (RO) units

• Domestic and commercial FRP filter vessels

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Technical Specifications