Oven
F24
The F24 error code on a Siemens oven indicates a fault with the oven’s temperature sensor (NTC sensor) or its associated wiring — it’s a moderately serious fault that will prevent the oven from heating correctly until resolved.
What does this error mean?
F24 tells you that the oven’s control board has detected an abnormal reading from the NTC temperature sensor — either the resistance value is out of range, or the sensor circuit has an open or short fault. The oven uses this sensor to regulate heat accurately, so when it fails, the appliance may refuse to heat, overheat, or shut down as a safety precaution. This is an electrical fault, not a gas issue, so careful DIY investigation is reasonable before calling an engineer.
Est. repair cost
£15–£35 DIY NTC sensor replacement; £80–£180 for a professional repair including callout and parts
🔍 Likely causes
🛠️ Step-by-step fix
Step 1 – Hard reset the oven: Switch the oven off at the wall socket (or trip the circuit breaker), wait 5 minutes, then restore power. Retry the oven. A transient fault or minor glitch can sometimes clear the F24 code without further action.
Step 2 – Check the oven’s error history in the manual: Some Siemens models log multiple fault codes. Confirm F24 is the active fault and not a residual stored code from a previous event.
Step 3 – Inspect the NTC sensor visually (oven must be OFF and fully cool): The NTC sensor is typically a small metal probe mounted inside the oven cavity, usually on the rear or side wall. Check for obvious burn marks, corrosion, or physical damage. Do not attempt this while the oven is warm.
Step 4 – Check the sensor connector: Locate the connector where the sensor cable meets the wiring loom (accessible by removing the back panel of the oven cavity — unplug the appliance first). Reseat the connector firmly. Look for burnt or corroded pins. If the connector is visibly damaged, it needs replacing.
Step 5 – Test or replace the NTC sensor: NTC sensors for Siemens ovens are widely available online (search your model number + ‘NTC sensor’). A replacement sensor typically costs £15–£35. Fitting involves removing two screws and unplugging the old sensor — a straightforward job if you’re comfortable working with unplugged appliances.
Step 6 – If the fault persists after replacing the sensor, stop DIY work: A persisting F24 after a confirmed sensor replacement points to a wiring loom fault or PCB failure — both require a qualified appliance engineer to diagnose safely.
📞 When to call a professional
Call a qualified appliance engineer if the F24 error returns after you’ve replaced the NTC sensor, or if you find burnt or melted wiring inside the appliance. Tell the engineer: ‘My Siemens oven is showing error code F24 — I’ve already reset it and [replaced the NTC sensor / inspected the connector], but the fault persists.’ This saves diagnostic time and money. Do not attempt to open or replace the main PCB yourself.
⚖️ Repair or replace?
A professional repair for F24 — covering callout, diagnosis, and parts — typically costs £80–£180 depending on whether it’s a sensor or PCB fault. If your Siemens oven is under 8 years old and has been reliable, repair is almost always the better value. For ovens over 10 years old where the PCB has failed, a replacement oven (budget £350–£600 for a comparable Siemens built-in model) is worth considering, as further faults become more likely.