Sensor Err
Worcester Bosch
Room temperature sensor failure or disconnection
Thermostat shows 'Sensor Err', 'SENS', or a similar message; room temperature reading is blank or shows dashes.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Failed internal NTC temperature sensor, Broken connection between sensor and main PCB, Moisture ingress damaging sensor, Firmware misreading sensor values
How to Fix / Troubleshooting
Safety first: Work on the thermostat only; do not open the boiler. If you are not comfortable opening the thermostat casing, contact a professional.
- Power cycle: Remove the thermostat from its base and take out the batteries (or disconnect low‑voltage power) for 1–2 minutes, then restore power. This can clear transient sensor read errors.
- Check environment: Ensure the thermostat is not installed in direct sunlight, above a radiator, or in a damp area, as extreme conditions can trigger sensor protection.
- Inspect for moisture: If the thermostat is in a humid area, remove it from the wall and allow it to dry in a warm, dry room for several hours. Do not use direct heat sources.
- If error persists: The internal NTC sensor or its connection to the PCB is likely faulty. These are usually not user‑serviceable; the thermostat assembly typically needs replacement.
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Repair Difficulty
Hard
4/5
Required Part
Smart Thermostat Main PCB (with Integrated NTC Sensor)
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