I want a thermal expansion valve. They are common in HVAC systems but I want one that operates around 200 degrees F. The ones designed for HVAC operate at much higher temperatures I believe. I did find one for sale at this link http://www.mcmaster.com/#temperature-regulating-valves/=o1znnq but I don't want to spend the $1000+ on it. So the easy solution is to make one. Now how... I have some ideas but I am just thinking out loud to see if there is any interest. Essentially, a bulb of gas expands in the presence of heat forcing a piston to extend from a cylinder. The piston causes a valve to open. As the temperature cools, the gas contracts, the piston recedes, and the valve closes. No electricity. Direct(ish) control.
No. No. No. No. Changed my mind. Wanna come down. To see this tiny ad:
permaculture bootcamp - learn permaculture through a little hard work