Temperature sensor, part 170003-0001, for Hanovia medium-pressure ultraviolet disinfection systems. It measures temperature in the treatment chamber and gives the controller the input it needs to protect the system when flow stops with a lamp still lit — the condition that overheats and cracks a quartz sleeve. Please note that this reference has been superseded: item 22186 is the current replacement and is the one to order for a new installation. Its matching sensor cable has been superseded in the same way, by item 22185. Reference number 2257-0508.