as a translator that allows your boiler to talk to external devices. The is often used for: External fault signaling
In some configurations, it may indicate a fault at the DE1 connection on the external safety device adapter. Common Causes of a D6 Fault Several underlying issues can trigger this lockout: viessmann d6 error
Because this error involves the combustion and venting system, repairs involving the fan, gas valves, or internal components should be performed by a Gas Safe registered engineer as a translator that allows your boiler to