Boiler shows E06, domestic hot water temperature unstable or no hot water, DHW sensor fault.

Safety first: Disconnect power before removing covers or accessing sensors.

• Locate DHW sensor: On combi boilers, the DHW NTC is usually mounted on the plate heat exchanger. On system boilers with cylinders, it may be in a sensor pocket on the cylinder.
• Check fit and contact: Ensure the sensor is fully inserted into its pocket and that thermal paste (if specified) is present for good heat transfer.
• Inspect wiring: Follow the sensor cable back to the control board, checking for damage or loose plugs. Reseat connectors.
• Test resistance: Measure the sensor resistance and compare with the Weishaupt chart. Replace the sensor if readings are out of specification.

When to call a professional: If replacing the sensor does not clear the fault, the control board or wiring harness may require professional diagnosis.