Vokera Common Fault and Error codes

Vokera Common Fault and Error codes

Vokèra boilers, like those of other manufacturers, utilize a system of fault and error codes to help users and engineers quickly identify and diagnose issues affecting boiler operation. Understanding these codes can significantly expedite troubleshooting and repairs. Here’s a summary of some common Vokèra boiler fault and error codes and their general meanings:

  1. A01: Ignition Failure – This error occurs when the boiler attempts to ignite but fails. Causes can include issues with the gas supply, ignition electrodes, or flue system.
  2. A03: Fan Fault – Indicates a problem with the fan, which is crucial for removing exhaust gases and drawing in fresh air for combustion.
  3. A04: Overheat Fault – The boiler has exceeded its safe operating temperature, possibly due to a blockage in the system, a faulty pump, or thermostat issues.
  4. A06: Flue Overheat Fault – Suggests that the flue or exhaust is overheating, which could be due to blockages or incorrect installation.
  5. A07: Domestic Hot Water (DHW) Thermistor Fault – Indicates an issue with the sensor that measures the temperature of the hot water being supplied.
  6. A08: Return Thermistor Fault – This error points to a problem with the sensor that measures the temperature of water returning to the boiler.
  7. A09: False Flame Detection – The boiler detects a flame when there should not be one, possibly due to an electronic fault or flue gas recirculation.
  8. A41: Return Thermistor Fault (specific models) – Similar to A08, indicating a fault with the return water temperature sensor.
  9. A77: Reversible Fan Fault – Indicates an issue with the fan’s ability to reverse its direction, which is necessary for certain boiler operations.
  10. AL10, AL20, AL21, AL26, AL28, AL34: Dry Fire, Overheat, or Flow Thermistor Faults – These codes indicate issues related to the boiler overheating or problems with the flow thermistor, which measures the temperature of water within the boiler.

Troubleshooting and Resolution

  • Ignition Failures (A01): Check the gas supply, ensure the ignition electrodes are clean and correctly positioned, and inspect the flue for blockages.
  • Fan Faults (A03): Verify the fan’s operation, check for obstructions, and inspect electrical connections.
  • Overheat Faults (A04, AL10, AL20, AL21, AL26, AL28, AL34): Check for system blockages, ensure the pump is operational, and verify the thermostat and thermistors are functioning correctly.
  • Flue and Thermistor Faults (A06, A07, A08, A41): Inspect the flue for correct installation and clear any blockages, and replace faulty thermistors as necessary.
  • False Flame Detection (A09): Consult a professional to check the electronic control unit and assess for flue gas recirculation.
  • Reversible Fan Fault (A77): This specific fault typically requires professional diagnosis and repair.


Vokèra boiler fault and error codes provide valuable insights into the system’s status and potential issues. While some problems can be addressed with basic troubleshooting, many require professional intervention due to their complexity or the need for specialized knowledge and tools. Regular maintenance by a qualified engineer can help prevent many common faults and ensure your boiler operates efficiently and safely.