Ariston Oven Error Code ER31

ER31 means the NTC temperature sensor circuit on the main control board is in an open circuit condition. The NTC thermistor is integrated directly onto the main board and is responsible for monitoring oven temperature. When this circuit fails open, the control system cannot read a valid temperature signal and generates the ER31 fault. The main board must be replaced to resolve this error.

You should not continue using the oven while ER31 is active. The error indicates the oven's temperature monitoring circuit is non-functional, which means the control board cannot accurately regulate heating elements. Operating the oven in this state risks uncontrolled overheating, which poses both a fire hazard and a risk of damage to the appliance.

The cost to repair ER31 on an Ariston oven typically involves the price of a replacement main control board plus labor. Board costs vary by model but generally fall in the range of $80 to $250 for the part alone. With professional labor, total repair costs commonly range from $150 to $400 depending on your location and the technician's rates.

Because the NTC sensor involved in ER31 is built into the main control board rather than being a separate plug-in probe, the repair requires replacing the entire main board. This involves working with mains voltage wiring and precise connector handling, so it is recommended that a qualified appliance technician perform the replacement. If you are experienced with appliance repairs and comfortable working safely with electrical components, you can source the correct replacement board for your specific model.

Resetting the oven by cutting power at the breaker and restoring it may temporarily clear the displayed code, but ER31 will return because the underlying hardware fault on the main board is still present. A power reset does not repair a failed NTC thermistor circuit. Permanent resolution requires replacing the main control board.