Sylphon hot water regulator

J.B.Bane

I am a heating contractor and have a gravity hot water system in my house circa 1920. Many years back I installed an oil fired boiler piped parrallel to the original hand fired coal or wood burning American Radiator Co. Ideal boiler. This system works very well. The old boiler has a device mounted in a 2" wye above the boiler in one of the supply pipes that old catologs refer to as a Sylphon hot water regulator. The purpose of the device is to close the draft gate on the boiler as the the water temperature rises and open again as the temp. comes down in the system. Weights on a bar can be varied to adjust the temp. range. This is a nonelectric control that uses a gas or volatile liquid inside a bellows to actuate the damper control. I still burn a lot of wood and it makes it much easier with this working to avoid overheating the house. Unfortunately the bellow part finaly gave it up after 85 years of working. Does anyone still make such a device or have any funtional used ones that have been saved?