Locking fault a/1/2 (8/1/6) - WM10 module not available or no communication

What does a/1/2 mean?

The WM10 module is not available, or there is no communication with it. This could be due to incorrect connection, a defective module, or the module not being recognized by the RC-thermostat. Heating circuit pump 1 will activate continuously. This is a locking fault, and the boiler will attempt to self-correct.

• WM10 module or bus circuit connected incorrectly or defective
• WM10 not recognized by the RC-thermostat

Click steps to track your progress.

1. 1

   Check the connections to the WM10 module and the bus circuit for secure fit.

2. 2

   Power cycle the boiler by switching it OFF and then ON again.

3. 3

   If the fault persists, contact a qualified service technician to inspect the WM10 module and RC-thermostat communication.