Heater shows correct temperature but actual water at tap is much cooler or hotter.

Safety: Use a thermometer to avoid scalding when checking actual water temperature.

• 1. Measure at outlet: Measure water temperature directly at the heater outlet if possible, then at the tap. Differences indicate mixing or losses in piping.
• 2. Check mixing valves: Inspect and adjust or replace any thermostatic mixing valves installed after the heater.
• 3. Sensor placement: Ensure the outlet NTC is firmly attached to the outlet pipe or in its designated well.
• 4. Replace sensors: If calibration is suspect, replace the NTC sensors with genuine Kospel parts.