what is the device called that shuts down a boiler if the water temperature gets too high?
It's called a temperature high-limit controller (with manual reset), sometimes called high-limit aquastat.
Boiler fittings: --------------------------------------... Safety valve: used to relieve pressure and prevent possible explosion of a boiler Water level indicators: to show the operator the level of fluid in the boiler, a water gauge or water column is provided Bottom blowdown valves Surface blowdown line Circulating pump Feedwater check valve or clack valve: a nonreturn stop valve in the feedwater line Steam accessories: ----------------------------- Main steam stop valve Steam traps Main steam stop/Check valve used on multiple boiler installations Combustion accessories: --------------------------------------... Fuel oil system Gas system Coal system Automatic combustion systems Other essential items: ------------------------------- Pressure gauges Feed pumps Fusible plug Inspectors test pressure gauge attachment Name plate Registration plate
