Cause of error code #W00

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

Outdoor Sensor Open

Solution for error code #W00

- Check to see if the Outdoor Sensor is connected.
- Check wiring connectons to outdoor sensor.
- Remove wires from terminals #3 and #4 on the boiler and check the resistance between them. If the reading shows an open circuit there is an open circuit.