Error [upd]: Viessmann D6

In systems with thermostatic radiator valves, a missing overflow valve can cause the system to "choke" when the radiators close, leading to the D6 code. Air Locks:

When a Gas Safe registered engineer arrives, they will likely take the following steps: viessmann d6 error

: Check the external flue terminal for any visible blockages or damage. In systems with thermostatic radiator valves, a missing