Ariston Cooktop Error Code E.27

Error code E.27 on an Ariston induction cooktop indicates that the dissipator temperature sensor on the Communicating Generator has been detected in an open circuit (CO) condition. The dissipator is the heat sink assembly responsible for managing thermal output from the induction generator electronics. This generator drives the high-frequency current through the induction coils, and its temperature must be continuously monitored to prevent thermal damage to the power electronics. The sensor associated with this component, typically a negative temperature coefficient (NTC) thermistor, provides real-time temperature feedback to the control board. An open circuit reading means the control board is receiving no signal from the sensor, which it interprets as a fault rather than a valid temperature value.

The most common root causes of an open circuit sensor fault are a broken or disconnected sensor lead wire, a failed thermistor element with infinite resistance, or a damaged connector between the sensor harness and the control board. In induction cooktops, vibration and heat cycling over time can cause wire fatigue, particularly at connector terminals or at the point where the sensor wire exits its housing. The control board cannot distinguish between a runaway temperature condition and a completely absent signal, so it halts operation as a precaution.

Diagnosing this fault requires inspecting the wiring harness from the dissipator sensor to the control board for any visible breaks, burns, or disconnected connectors. The thermistor itself should be tested with a multimeter: an open circuit or infinite resistance reading across the sensor terminals confirms internal sensor failure. If wiring and connectors check out, the control board input circuit may itself be at fault, though this is less common.