Viessmann A6 Fault

Viessmann A6 Fault

When the Viessmann A6 fault code is activated, it means that there is no communication between the control units of a boiler and the burner. Such error implies that these two units fail to communicate well hence affecting the functioning of a boiler including its ability to ignite and work properly. Below are some possible causes and ways of resolving A6:
Causes of the A6 Fault Code

Wiring Problems: Defective or loosely connected cables between a control unit of a boiler and that of a burner can interrupt communication leading to an occurrence of A6.

Malfunctioning Control Units: Either main control unit in a boiler or control unit for its burner may be broken down so as to stop their effective communication with each other.

Software or Configuration Failures: In addition, failures within software or configuration settings on these control units frequently cause communication issues thereby resulting in this particular fault code A6.

Power Supply Problems: Disruptions or fluctuations in power fed towards boilers or control units can hinder them from communicating.

Troubleshooting and Resolving the A6 Fault Code

Inspect Wire Connections: Inspect wires connection joining control unit in your boiler with one from its burner for signs showing damage, weariness, or looseness. Fasten any loose connections by replacing damaged wires when necessary.

Reset Your Boiler: Try resetting your device to find out if this resolves the problem on communication error. This may sometimes help address temporary fault codes due to minor glitches concerning software operation.

Look at Control Units: Check whether there are any visible signs of malfunctioning present on both these control units (from your boiler and burner). It should be done by an expert due to their complexity thus requiring skills during fixing.

Follow Manual Instructions: Always consult your heating system’s user guide for some specific guidelines and strategies aimed at solving A6 fault code. It gives more details on how you can deal with problems related to communications effectively.

Professional Diagnosis & Repair Works – At times, Viessmann certified technician or a registered Gas Safe engineer may be called upon to help in the diagnosis and rectification of these complex communication errors which may require software diagnostic tools or configuration adjustments.

Regular Maintenance – Have your boiler regularly serviced by a professional. This will prevent communication errors and other faults by ensuring all parts including wires and control units are working well.


The Viessmann A6 fault code shows that there is breakdown of communication between the boiler’s control units as well as the burner’s own hence it needs careful assessment and possibly intricate troubleshooting. The addressing of this fault often involves technicalities requiring expert assistance. Regular maintenance of boilers will also prevent such communications errors from occurring thereby guaranteeing an efficient heating system for one’s home.