Product Information: The thermistor increases the circuit resistance as it gets colder The printed circuit board sends a current to the thermistor and can tell whether a decrease or increase in heat is needed by the resistance provided by the thermistor.
This part is present in 67 different boilers in the Worcester range including the Worcester CDI 25 , CDI 30 , CDI 35 , CDI 40 , CC1 NG FSN CONDENSING COMBI.