Systems Help Center

This bulletin from C.A. Dunham Co. is from 1916 and features the Dunham Blast Trap and Its Application.

Packless radiator supply valves kept air from working its way into a vacuum system. This bulletin from C.A. Dunham Co.

This bulletin from C.A. Dunham Co. is from 1916 and features the Dunham Reducing Pressure Valve and Vacuum Pump Governor.

This circa-1916 bulletin contains helpful information about the Dunham Vapor Heating System. Thanks to David Cordes for sharing.

The Dunham Victory line appeared in 1943 and had to meet Government specifications since we were at war. Note how the Vari-Vac system was then called the Dunham Coordinat...

This is a very clear explanation of the Hartford Loop. It's from the Western Plumbing and Heating Journal and it appeared in April, 1943.

Thanks to John Van Hoesen for finding and sharing this interesting article about how to fire a steam boiler in an elementary school, circa 1916. It urges the fireman to k...

The Hoffman - A Venting Valve for Every Service shares the Hoffman story, as told 30 years after George D. Hoffman introduced his first vent. Wonderfully clear language h...

This is an interesting article about the steam loop from The Manufacturer and Builder magazine, January, 1892. It still works today.

Here is a nice explanation of thermostatic traps by Austin Roche, Chief Engineer for Hoffman Specialty. This appeared on June 13, 1952.