Thermostatic Faucets

Hi,

we have one of these thermostatic faucets at home and i’m just wondering how it works. When you set the temperature, it manages to automatically mix the hot and cold water for you so you always get a constant temperature even if the temperature of the piped in hot water changes. There are no electronics involved so i’m pretty curious how it works. anyone can shed some light? thanks!

Does it work when the “hot” water is not hot at all?

when you set it to a temperature of say 38C, and the hot water is not hot enough, no water comes out at all when you turn on the tap.

Googling for temperature/pressure balancing faucet/fixture would work.

have you found a site which explains it? i tried googling before posting here but all i could find were sites advertising products which have this feature. best result i got was a patent for it, but i don’t really understand it and i wasn’t sure if it was referring to the same thing.

Back in the 1970s they used a little bimetallic strip inside the faucet. It reacts to temperature changes by bending to one side or the other and that motion was used to control the flow of hot/cold. I remember seeing a cutaway of the system in “How Things Don’t Work”.

Dunno if things have changed much in the last 30 years but that seemed like a pretty straightforward way of doing it.