Bk 888-239 Rubber Washer Dielectric Union

Product Description

The BK 888-239 is a replacement rubber washer designed for use with 1/2 inch galvanized dielectric unions. Made from Buna-N rubber, this washer provides a reliable seal between the metal union components, helping to maintain the dielectric separation that prevents galvanic corrosion between dissimilar pipe materials. Plumbers and pipefitters install this washer as a service part when a worn or degraded washer allows leakage or compromises the union's insulating function. At 0.007 pounds, it is a lightweight, low-cost repair component stocked for routine service calls.

This washer is used in residential and light commercial plumbing systems wherever dielectric unions join copper and galvanized steel pipe. Common applications include water heater connections, boiler supply and return lines, and other mixed-metal piping configurations where electrolytic corrosion control is required. It is sold individually and is well-suited for keeping on hand as a standard service replacement.

Key Features

• Buna-N rubber construction for durability and chemical resistance in potable water service
• Sized for 1/2 inch dielectric unions
• Designed as a direct replacement for worn or damaged union washers
• Compatible with Mueller, BK, and other standard dielectric union brands
• Lightweight at 0.007 pounds for easy bulk stocking

Compatibility

Fits Mueller, BK, and other standard brand 1/2 inch galvanized dielectric unions. Confirm washer seat diameter before installation to ensure proper fitment with non-Mueller or non-BK union bodies.

Installation Notes

Shut off the water supply and depressurize the line before disassembling the union. A licensed plumber should perform dielectric union service in jurisdictions requiring permitted plumbing work. Inspect the union seat for scoring or corrosion before installing the new washer, as a damaged seat will cause repeat leakage regardless of washer condition. Tighten the union nut to hand-snug plus firm wrench pressure without over-torquing, which can deform the rubber and reduce seal life.

Technical Specifications

• Size: 1/2 inch
• Material: Buna-N rubber
• Weight: 0.007 pounds
• UOM: Each
• Minimum Order Quantity: 5
• UPC: 00032888882393

Standard Information

• Brand: BK
• Manufacturer Part Number: 888-239