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McDonnell & Miller is a leader in engineering and manufacturing boiler and liquid level controls, low-water cutoffs, and flow switches for steam and hot water boilers in industrial, commercial and building applications.

Our History

For more than 95 years, McDonnell & Miller has been the leader in engineering and manufacturing a comprehensive line of boiler controls, liquid level controls and flow switches for steam and hot water boilers.

In 1924, recognizing the need for an improved way to protect low pressure steam heating boilers, Everett Nicholas McDonnell, in collaboration with Pat Miller, formed McDonnell & Miller (M&M). Its first products were automatic boiler water feeders for low pressure steam boilers. The company prospered, and during the 1930s it developed many products that are still used today, including a patented cold feed valve, and a quick hook-up fitting that made the valve very easy to install.

In the mid 1930s, new boilers with automatic burners created the need for a safety device that would turn off the burner if a low water condition developed. This led to the development of M&M’s low water cut-off product line for hot water and steam boilers. By the end of the decade, code authorities were mandating that pressure boilers be protected with some type of low water sensing device.

Pent-up consumer demand after World War II led to updates in automatic heating equipment. M&M reaped the benefits of this demand, and built a new factory in the late 1940s. Manufacturing, though considerably modernized, still takes place in this facility today.

M&M built its first flow switch in the 1930s for use in steam locomotives. Sales declined with the passing of the steam locomotive, but in the early 1950s, new market opportunities arose in commercial and industrial air conditioning to prevent a freeze-up of the chiller. Many new flow switch models were added, additional markets developed, and M&M created one of the broadest flow switch lines in the world.

In 1971, M&M was acquired by ITT Industries, Inc. The facility received ISO 9001 and ISO 14001 certification as the result of its dedication to designing, producing and marketing the very highest quality products.

On October 31, 2011, Xylem completed its spinoff from ITT Corporation, and began a new chapter as a leading global water technology company with operations in more than 150 countries.  Formed from several of ITT’s water and fluid handling and analytics businesses, Xylem brings to the marketplace a passionate, talented, and experienced workforce; well-known industry-leading brands and water solution products, and a shared commitment to making a difference in communities around the world.