Ideal 170917 Thermistor Boiler Control Kit

The Ideal 170917 is a thermistor kit intended for boiler control duties on Ideal M Series appliances. A thermistor is a temperature-sensitive resistor: its electrical resistance changes as the temperature around the probe changes, which lets the boiler's control board read how hot the water or component actually is and adjust firing, pump and safety behaviour accordingly. This kit is listed under the thermostats, thermistors and sensors spare part category and is supplied by Ideal Spares for servicing and repair work on the M Series range.

• Boiler locks out or fails to fire, with a temperature or sensor related fault code shown on the display
• Hot water or heating temperature that fluctuates widely instead of holding steady
• Erratic or implausible temperature readings reported by the boiler controls
• Short cycling, where the boiler fires and shuts down repeatedly over a short period
• Intermittent operation that clears when the sensor wiring or connector is disturbed

• Confirm the appliance model and serial number from the data badge, as Ideal has produced several variants across the M Series range
• Check the existing sensor and its connector against the part number 170917 before fitting
• Inspect the sensor pocket, O-ring or sealing washer at the same time, as these are commonly disturbed during replacement