Boiler displays E17, outdoor temperature compensation does not work correctly.

Safety: Turn off power before working on control wiring.

• Locate sensor: Find the outdoor sensor on the north or shaded wall. Ensure it is not exposed to direct sunlight or other heat sources.
• Inspect cable: Check the cable from the sensor to the boiler or room controller for damage or joints exposed to moisture.
• Measure resistance: Disconnect the sensor and measure resistance. Compare with Klimosz NTC chart. Replace if out of range.
• Check terminals: Tighten and clean the terminals where the sensor connects to the boiler control board or weather-compensated controller.
• Recalibrate curve: After sensor replacement, verify and adjust the heating curve settings in the Klimosz controller menu if necessary.