Systems Help Center

The Intensifier, invented by W.C. McKeown, does a job similar to the one performed by Honeywell's Heat Generator. Thanks to Steve Pajek for finding this patent.

Here is an interesting article from Western Plumbing and Heating Journal, April 1937, and a real call to arms!

Here is a patent issued to August Kehm for his tee fitting, later used by Bell & Gossett for their Monoflo. Thanks to Gerry Gill for the research, and for finding the pat...

Thanks to Gerry Gill for finding Oliver Schlemmer's patent for the O-S fitting, which made one-pipe hot water heating possible.

Edward Parker received this patent in 1911 for a different way to pipe a hot water radiator. Thanks to Steve Pajek for finding it and sharing it with us.

One of the earlier gravity-hot-water-heating devices. Water would stratify in the horizontal main, with the hottest water rising to the top of the pipe. It left the tee a...

Special thanks to George Peteya, P.E., of Slant/Fin for sharing this circa-1955 Sarcotherm Installation and Service Manual for Modulating Outdoor-Indoor Controls (Sarcoth...

Thanks to H.L. Bent of Melroy Plumbing & Heating Inc. in Baltimore for sharing these instructions and this photo of a fine old job.

This is probably the earliest outdoor reset control. They lasted a long time! The brochure is from 1943.

This is one of the first attempts to move the attic expansion tank in a gravity hot water heating system to the basement. Thanks to Alex Marx for doing the scan for us.