How to Turn on Vaillant Boiler Without a Thermostat
If your Vaillant boiler doesn’t have a thermostat or the one you have isn’t working, don’t worry you can still turn your heating on manually. This guide will show you how to use your boiler without a thermostat so you can stay warm.
Table of contents
Why You Might Need to Use Manual Controls
You might need to turn on your boiler manually if:
- Your thermostat is broken or not responding
- You haven’t installed a thermostat yet
- You’re waiting for a new thermostat or a technician to fix it
In these cases, you can use your boiler’s control panel to turn on the heating yourself.
Steps to Turn on Vaillant Boiler Without a Thermostat
Time needed: 10 minutes
Follow the below steps to turn on vaillant boiler without a thermostat:
- Look for Manual Controls
Check if your boiler has manual dials or switches. Look for ones with heating symbols or temperature settings. Most Vaillant models include these.
- Find the Control Panel
Go to the front of the boiler and open or check the control panel. You’ll usually find:
Power button or switch
Temperature dials
Heating switches - Turn on the Boiler
Switch the boiler on by pressing the power button or flipping the switch. It may be labeled “ON/OFF” or show a power symbol.
- Set the Heating Temperature
Turn the temperature dial:
Clockwise to make it warmer
Counterclockwise to lower the heat
Look for markings like “Low,” “High,” or specific numbers. - Make Sure the Pump Is On
Some systems have a separate switch for the pump. This pump moves hot water through your radiators or underfloor heating. Make sure it’s switched on.
- Give It Time to Heat Up
Your boiler may take a few minutes to heat the water and start warming your home. You’ll feel heat in the radiators or get hot water from taps.
- Keep an Eye on the Heat
Since there’s no thermostat, you’ll need to:
Check how warm your home feels
Turn the boiler down or off if it gets too hot
Remember, it won’t shut off by itself-you have to do it manually.
When to Call a Gas Safe Engineer
Call a Gas Safe registered engineer if:
- You smell gas or suspect a leak
- The boiler makes loud or strange noises
- The boiler shows error codes or warning lights
- You don’t feel confident operating it safely
Safety Tip: Never open or repair a gas boiler yourself unless you’re trained and certified. A professional can fix faults and ensure your system runs safely.
A Few Extra Tips
- Running your boiler without a thermostat may use more energy
- You might notice uneven temperatures in your home
- For better control, think about getting a smart thermostat
Smart thermostats like RF or Wi-Fi models work well with Vaillant boilers. Many also work with Google Home or Alexa for voice control.
Final Thoughts
You can use your Vaillant boiler without a thermostat. Just follow the steps above to turn it on manually and stay warm. But don’t forget to monitor the temperature and turn it off when it gets too hot. For long-term comfort and energy savings, it’s a good idea to install a proper thermostat.
Frequently Asked Questions
Secondly, locate the boiler’s controls. Depending on the Vaillant boiler model, these are often found on the front panel of the appliance and may contain a temperature control, power button or switch, and other settings. Once you’ve identified the boiler controls, it’s time to activate the boiler.
Ensure the electrical supply to the boiler is turned on. This may be from a switched socket, or a fused spur located near the boiler. This switch should be left ON continuously to operate the boiler. Turn the boiler ON by turning the ON/OFF control (5) from the ‘0’ position to the ‘I’ position.
Why is my Vaillant boiler not firing up? A Vaillant boiler might not fire up due to frozen pipes, power supply issues, or a need for resetting.
Will turning my boiler off cause problems? Money aside, the most important thing to consider when switching off your boiler at the mains is the safety of your family. Fortunately, switching off your boiler at the mains is perfectly safe.
