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Error code reference

Ariston Oven Error Code ER31

NTC sensor on main board is in open circuit.

Ariston codesAriston oven codes

NTC sensor on main board is in open circuit.

First step from the service manual

Replace Main Board.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What ER31 means on a Ariston oven

Error code ER31 on an Ariston oven indicates that the NTC (Negative Temperature Coefficient) sensor circuit integrated on the main control board has been detected in an open circuit condition. An NTC thermistor works by decreasing its electrical resistance as temperature rises. When the oven's control system reads an open circuit from this sensor, it means the circuit is broken and no valid resistance signal is reaching the board's processor, preventing the oven from accurately monitoring its internal temperature.

The NTC sensor referenced in ER31 is located directly on the main board itself, which distinguishes this fault from external probe errors. An open circuit in this context means the thermistor element or its associated circuitry on the board has failed completely, resulting in infinite or unmeasurable resistance. This prevents the control system from regulating heating cycles, and the oven will not operate safely without a valid temperature reference signal.

Because the faulty NTC is embedded within the main board assembly rather than being a standalone replaceable probe, the corrective action is replacement of the entire main control board. There is no field-level repair for the integrated thermistor itself. Causes can include heat stress on the board over time, component fatigue, or electrical surges that damage the thermistor element or its solder joints. A qualified technician should confirm the ER31 code before proceeding with board replacement.

Source: manufacturer service documentation.

Common causes of ER31

  1. 01

    Failed NTC thermistor on main board

    Part replacement

    The NTC thermistor integrated into the main control board has developed an open circuit, either through component fatigue or heat stress over time. This is the primary cause indicated by ER31 and requires main board replacement.

  2. 02

    Heat damage to main board

    Part replacement

    Prolonged exposure to high oven cavity temperatures can degrade solder joints and components on the main board, causing the NTC circuit to fail open. Inspect the board for visible heat discoloration or burnt areas near the thermistor circuit.

  3. 03

    Electrical surge or power spike

    Part replacement

    A voltage surge from the mains supply can damage sensitive components on the main board, including the NTC thermistor circuit. If the error appeared after a power outage or surge event, board damage is a likely cause.

  4. 04

    Cracked or broken solder joint on NTC circuit

    Part replacement

    Thermal cycling over years of use can cause solder joints connecting the NTC thermistor to the board traces to crack and open. This results in the same open circuit reading as a failed thermistor component itself.

See the test procedure for each cause

Frequently asked questions about ER31

What does ER31 mean on a Ariston oven?
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.
Can I fix ER31 on my Ariston oven myself?
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.
Is it safe to use my Ariston oven when ER31 is displayed?
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.
Will resetting my Ariston oven clear the ER31 error?
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.
How much does it cost to repair an Ariston oven showing ER31?
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.

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