Cause of error code #W02

Blinking Screen – Press “Reset” key to view this message

- DHW Sensor Open

Solution for error code #W02

- Be sure the optional DHW Sensor (54157) is connected.
- Remove the wires from terminals #5 and #6 on the boiler and check the resistance between them.
- If the resistance is above 10 k Ω, check the resistance at the sensor.
- If the reading at the sensor is the same, replace the sensor.
- If the reading at the sensor is lower, replace the wiring.