Resideo - Honeywell Home FM911

FM911 by Resideo Honeywell Home is a 1/2" NPT backflow preventer and boiler fill valve combo assembly designed for reliable, code-compliant boiler operation. This compact unit integrates essential safety and filling functions in a single, easy-to-install package for residential heating systems.

Engineered for durability and ease of installation, the FM911 helps prevent cross-connection with potable water while delivering precise boiler fill. The 1/2" NPT connections ensure compatibility with standard piping, making retrofit or new installs straightforward.

Designed to meet common standards for residential plumbing, the FM911 reduces risk of backflow contamination and guarantees a consistent boiler fill that supports efficient combustion and heat delivery. Its compact profile frees up space in tight boiler rooms and makes service routines faster.

• 1/2" NPT connection for quick, secure installation
• Integrated backflow preventer protects the potable water supply
• Precision boiler fill valve for accurate water level control
• Durable materials for long-term reliability
• Compact combo assembly designed for tight boiler rooms

Backed by Honeywell quality, this FM911 combo assembly delivers dependable performance, helping protect your home’s heating system and peace of mind.