Boiler displays A16, burner output limited, may show outside temperature error on weather-compensated systems

Safety: Isolate power before working on control wiring.

• Check sensor location: The Hoval outdoor sensor should be mounted on a north or northwest wall, away from direct sun or heat sources. Relocate if incorrectly installed.
• Inspect wiring: Follow the cable from the sensor to the boiler controller. Repair any visible damage and ensure correct polarity if required.
• Measure resistance: A technician can measure the sensor resistance and compare it to the Hoval temperature/resistance table. Replace if faulty.
• Until replaced, the boiler may operate with default values, but efficiency and comfort may be reduced.