The Ideal Boilers control thermistor is designed for use in Esprit, Isar, Esprit 2, and Evo boilers. The thermistor decreases circuit resistance in line with temperature increases. A boiler control board sends a current to the thermistor, deciding whether a decrease or increase in heat is required by reading the relative resistance.

• Domestic hot water sensor
• Secured in place by a U-shaped pin