Bk Mueller 511-804HP 3/4 Inch Malleable Iron Square Plug

Product Description

The BK MUELLER 511-804HP is a 3/4 inch malleable iron square plug designed to seal threaded pipe ends in plumbing, gas, and steam distribution systems. With a liquid and gas pressure rating of 300 psi and a steam pressure rating of 150 psi, this Class 150 fitting handles the demands of both residential and light commercial installations. The galvanized finish provides corrosion resistance for long service life in exposed or damp environments. Licensed plumbers and pipefitters install this type of plug to cap unused branch outlets, dead-end lines, or test ports during system commissioning and maintenance.

This square plug is suited for threaded pipe systems carrying liquid, gas, or low-pressure steam. The 3/4 inch size fits standard NPT female-threaded fittings and is a common stock item for plumbing rough-in work, gas distribution manifolds, and steam heating systems. The square head design allows installation and removal with a standard pipe wrench or adjustable wrench without the need for specialized tooling.

Key Features

• 300 psi liquid and gas pressure rating for reliable sealing in pressurized systems
• 150 psi steam pressure rating suitable for low-pressure steam heating applications
• Malleable iron construction provides strength and impact resistance over cast iron
• Galvanized finish resists corrosion in damp or outdoor-adjacent installations
• Square head profile accepts standard pipe wrench for easy installation and removal
• Class 150 rated threaded fitting meets common plumbing and gas system requirements

Compatibility

Designed as an OEM-style replacement or stock fitting for standard 3/4 inch NPT threaded pipe systems in plumbing, gas, and steam applications.

Installation Notes

Installation should be performed by a licensed plumber or pipefitter in accordance with applicable local plumbing and mechanical codes, including the IPC and IFGC where relevant. Shut off and depressurize the system fully before removing or installing any threaded plug. Apply appropriate thread sealant or PTFE tape to the male threads before installation. Do not overtighten, as malleable iron threads can be damaged by excessive torque.