Boiler displays 10; no heating or hot water, which may indicate a flue or ventilation issue.

Safety first: Turn off the boiler and do not attempt to use it until checked. Flue gas faults can lead to a carbon monoxide risk. Contact a Gas Safe registered engineer immediately.

• Ventilation check: Ensure boiler cupboard vents (if required) are not blocked and that the boiler has an adequate air supply.
• External flue inspection: From outside, check for obvious obstructions or damage to the flue terminal.
• Engineer tasks:
  • Perform combustion analysis with a flue gas analyzer.
  • Inspect and clean the burner and heat exchanger.
  • Verify flue integrity, seals, and slope.
  • Test or replace any flue gas temperature or safety sensors fitted on the Vokera model.

Do not attempt DIY repairs on flue or combustion components.