Viessmann D6 | Error

In some HVAC control setups, a D6 may point to a communication break between the thermostat and the main control board. Step-by-Step Troubleshooting

If you hear , the igniter or ignition module may be faulty. If you hear clicking but no roar , the gas valve or gas supply is the issue. viessmann d6 error

The control unit has detected an issue with the response or speed signal of the internal circulation pump. Digital Input DE1: In some HVAC control setups, a D6 may