The Halstead thermistor decreases circuit resistance in line with temperature increases. The printed circuit board of a boiler sends a current to the thermistor, deciding whether a decrease or increase in heat is needed by reading the relative resistance. It is designed for use in Finest, Ace, Wickes combi and Wickes boilers.
Genuine replacement part for Halstead
Technical specification
TypeThermistorManufacturer Model No500590Brand NameHalstead