CodeRegistry
Brands
  1. Home
  2. Viessmann
  3. Vitodens 200 Boilers
  4. A4
About·Privacy·Terms

CodeRegistry — Your global library for technical solutions.

For your safety: always follow the equipment manufacturer’s official manuals. CodeRegistry is an independent help site and is not affiliated with the brands listed here.

A4

Fault A4 - Incorrect coding address

Viessmann · Vitodens 200 Boilers

What does A4 mean?

This fault indicates that a specific coding address (0B8:006) might have an incorrect value, affecting boiler operation.

Common Causes

  • Incorrect setting for coding address 0B8:006

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Verify the current value of coding address 0B8:006.

  2. 2

    Change the value of coding address 0B8:006 accordingly.

  3. 3

    Restart the boiler for changes to take effect.

Browse all codes in this manual (21)
Verified technical data. Last updated: April 2026

Related Faults

06 / 07Fault 06 or 07 - Insufficient air supply or vent blockage14Fault 14 - Ignition failure or gas supply issue14 (multiple boilers)Fault 14 (Multiple Boilers) - One boiler locks out while others run
Source: Viessmann Vitodens 200 Boilers
Open Manual (Page 7)Search more codes in this manual