Viessmann D6 Error <REAL »>

The D6 error appears most commonly on:

, your system is likely still operating normally, but it is flagging an issue with an external component. Unlike high-priority lockout codes that shut your heat off immediately, the D6 code is a communication signal typically related to an EA1 extension module What is the Viessmann D6 Fault? viessmann d6 error

Here is the action plan depending on your diagnosis: The D6 error appears most commonly on: ,

On older Viessmann units (pre-2008), a physical air pressure switch with rubber hoses is used. These hoses can crack, or the diaphragm inside the switch can fail. These hoses can crack, or the diaphragm inside

On Vitodens 200-W and 300-W series boilers, the D6 fault code indicates that digital input DE1 on the EA1 extension module is reporting a fault from an external appliance.

| Repair Action | Typical Total Cost (UK/EU) | |---------------|----------------------------| | Loose cable reseated | £80–£120 call‑out fee | | Replace Vitotronic display | £200–£400 | | Replace main PCB | £400–£800 | | Major electrical repair | £600+ |

The D6 error appears most commonly on:

, your system is likely still operating normally, but it is flagging an issue with an external component. Unlike high-priority lockout codes that shut your heat off immediately, the D6 code is a communication signal typically related to an EA1 extension module What is the Viessmann D6 Fault?

Here is the action plan depending on your diagnosis:

On older Viessmann units (pre-2008), a physical air pressure switch with rubber hoses is used. These hoses can crack, or the diaphragm inside the switch can fail.

On Vitodens 200-W and 300-W series boilers, the D6 fault code indicates that digital input DE1 on the EA1 extension module is reporting a fault from an external appliance.

| Repair Action | Typical Total Cost (UK/EU) | |---------------|----------------------------| | Loose cable reseated | £80–£120 call‑out fee | | Replace Vitotronic display | £200–£400 | | Replace main PCB | £400–£800 | | Major electrical repair | £600+ |