In this presentation, Gary Klein shares important information about air source heat pump water heaters (HPWH), with particular attention paid to where the warm air comes ...
Honeywell’s Unique Valve
Mark Honeywell invented the Unique Valve in the early 1900s. It gave him a way of connecting a hot-water radiator at just one side instead of two sides. The Unique valve opened with a quarter turn and used a baffle to direct the water into the radiator. The cooler water flowed by the hot water and entered the Unique valve on the other side of the baffle. In this video excerpt from his Classic Hydronics seminar, Dan Holohan teaches us about the origins of Honeywell’s Unique Valve and shows us how it works.
Want to learn more? Read Dan Holohan’s book Classic Hydronics: How to Get the Most From Those Older Hot-Water Heating Systems.
Leave a comment
Related Posts

In this all-technical three-hour seminar, Dan Holohan will give you a Liberal Arts education in those Classic Hydronics systems. He’ll have you seeing inside the pipes as...
We always have turkey for Thanksgiving. I mean who doesn’t? My job wasn’t to cook it, though; it was to eat it.