- 1. Check the thermostat
Ensure the thermostat setting is high enough to activate the heating. If the setting is below the ambient room temperature then the heating won't come on.
- 2. Check the timer
Make sure the timer has been set correctly, confirm the morning and evening times have been set the correct way round. Timers can be set to run Off, On continuously, Once, Twice — double check that the on/off timer settings are as you expect them to run.
- 3. Check the pilot light
If your appliance has a pilot light then on the front of the boiler there should be a view port to see if the pilot light is alight, if not then an error code might indicate the pilot light has gone out. If the pilot light has gone out, there should be instructions on the front of the boiler or inside the boiler door as to how it should be relit (pilot lights tend to be in boilers over 18 years old). The instructions will also be in the instruction manual if you cannot find them on the boiler.
- 4. 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.