• Domestic & General and our manufacturer partners will only conduct boiler servicing and repairs by using suitably qualified engineers. For gas and LPG, we will use a Gas Safe registered engineer and for oil, an OFTEC registered technician.

    Annual services should be conducted in summer months where possible to ensure your appliance is in optimum condition prior to the intensive use it will receive over winter period.

    An annual boiler service will check the safe functioning of your appliance including but not limited to:
  • 1. It is correctly set and adjusted to ensure the fuel is burning correctly.
  • 2. It is of a type suitable for the room in which it is located. See the “Guide to boiler types” Topic for guidance on boiler types, always check the user manual for your boiler's specification and specific installation requirements and follow the advice from qualified installation engineers.
  • 3. It is physically stable, securely fitted and properly connected to the gas (or other fuel type) pipework.
  • 4. There is an adequate and permanent air supply suitable for the appliance type installed.
  • 5. Any flues or chimneys are operating correctly.
  • 6. All safety devices function correctly.
  • 7. Check that the main components of the boiler are correctly functioning.
  • 8. If you have misplaced or lost your user manual, you can locate a replacement manual from this list of Vaillant boilers (please have your model number to hand).
  • We update the maintenance tips and troubleshooting guidance from time to time and aim to make it as helpful as possible. The purpose of the maintenance and troubleshooting section of this website is to provide you with general guidance. Please ensure you read and follow our instructions carefully and do not undertake the maintenance or troubleshooting unless you are aged 18 or over, are competent to do so and are confident that you can complete the maintenance. If in doubt do not attempt any actions and where an appliance is gas fuelled refer to a Gas Safe engineer for assistance.

    This website is not intended to be a substitute for professional advice and does not:
    - cover every reason that your product could fail;
    - cover all of the maintenance that can be undertaken for your product;
    - supersede any advice in your instruction manual or from your product manufacturer.

    Do not carry out any maintenance or use the troubleshooting guide if it puts you or anyone else in danger or if you believe it may cause damage to your, or another person’s property.