• 1. What is a timer?
    A boiler timer allows very basic timing functions to be set on your central heating. They generally only allow one timing pattern to be set, so all days would have the same timings for heating and hot water.
  • 2. What is a thermostat?
    A room thermostat is a wall mounted device that detects the ambient of the home and allows the user to set the central heating to a specific temperature. The optimum location for these devices are hallways and landings rather than rooms that can be isolated by the closure of doors. They should be positioned away from obstructions.
  • 3. What is a Programmer?
    A boiler programmer is a device that allows a user to set the time the heating and hot water is needed. Programmers allow different patterns to be set according to each day, so week days may have different requirements to the weekends for example.
  • 4. What is a thermostatic radiator valve (TRV)?
    Known as a TRV, a thermostatic radiator valve is a self regulating valve. It works by sensing the individual room temperature, adjusting accordingly and shutting off the radiator when the desired temperature is reached. By fitting one to each radiator, you can easily control the temperature in each room, which helps to improve comfort in your home and save money and energy. They are recommended by the government and Energy Saving Trust as they are energy efficient.

    Ideally, TRVs should be well exposed and not obstructed by curtains or blocked by furniture.
  • 5. 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.