Solving ongoing issues with your boiler

Most boiler re-pressurising can be done from the lever located directly underneath your boiler. You will only need to make a small and slow adjustment turn to increase the pressure. Please see your boiler instruction manual or do an internet search to find out how to do this on your specific boiler model. 

There is no harm in turning your boiler off and then on again. The buttons are made for use and you can refer to your instruction manual or do an internet search to find out how to do this.

Meter issues are the responsibility of the gas supplier. If you have a low battery notice on your meter or it is a meter fault (of any description) please contact your gas supplier.

Is there a fault code flashing on the front of the boiler?

If it is flashing, put the fault code, make and model of your boiler into Google, (for example Boiler Make - Glow Worm Model - 30CXi Fault code - F1). This should help you see what the problem is.
 
If your fault code says “low central heating system pressure”, or “temperature fault”, check the pressure gauge and top up as required.

If your fault code says "no ionisation", or "interrupted gas supply", try resetting the boiler. If this still does not solve the problem, please contact us.

If you have an older style boiler which doesn’t show fault codes, please contact us so we can help to identify the issue.

You can ask Vaillant technical questions and get instant answers using their online Ask Valliant service.

If you're having problems this type of boiler click the link to access the Worcester-Bosch boiler troubleshooting tool.

• The boiler will display the fault code F22 if the pressure is too low. 
• Underneath the appliance you will see a filling loop. This is silver in colour with a flexible connection attached to it.
• You will see a black handle and isolation valve screw under the boiler.
• Using a flathead screwdriver, turn the isolation valve to the left so that it is in a straight line and is in the same direction as the pipe located next to it.
• Turn the black valve to the left to adjust the pressure. 
• You should hear water coming through the system after doing this.  
• When the pressure gauge reader on the boiler says the measurement is at about 1.1-1.2 bar, turn the black valve to right again to close off the pressure valve.
• Using a flathead screwdriver, turn the isolation value screw to the right so that it is in a vertical position.
• Check that you have turned both valves off and that there aren’t any obstructions to the filling loop.
• Now looking at the boiler screen, watch the pressure level adjust so that it is now above the lowest line. 
• The fault code will disappear, and your boiler will now be fully functioning. 
   

• If your boiler pressure gauge needle is in the red waring area, for example reads below 1 bar on the pressure gauge, you will need to repressurise your boiler. Your boiler should have come to with an internal filling key which can be used to repressurise it. Instructions on where to find this key are below.
• Before repressurising, turn the power off to the boiler. 
• Once the power is off, look underneath the boiler. There is a white tray located below which can be removed. 
• Using the handle on the tray remove it so that you can fully see underneath the boiler.
• In the white tray you have just removed, you will see there is a white key. 
• Remove the key by pulling it away from the tray. 
• You will see a black coloured hole manifold underneath the boiler. 
• You will need to fit the key inside this hole. 
• The key will have a white arrow on the outside of it. 
• You will see that the black hole manifold has two symbols on it, one with an open padlock icon and one with a locked padlock.
• Insert the key into the black plastic manifold with the arrow in line with the open padlock.
• Turn the key so that it is now in the locked padlock position. 
• There is a white plastic screw nut located directly next to the key.
• Turn the screw nut anticlockwise. 
• As you start to turn the key you will hear water entering the system.
• Stop turning the screw nut once this happens. 
• Now look at your pressure gauge reader.
• You will see the needle reader on the pressure gauge is moving.
• Once the needle is measuring 1.5 bar (this will be in the green coloured section), you will have enough pressure within the system.
• Retighten the white screw nut until you hear the water stop running.
• Turn the white internal filling key back to the open padlock position.
• You may need to have a cloth ready to wipe away any excess water that drips from the boiler.
• You can now remove the white internal filling key.
• If a large amount of water comes out of the boiler, check you have fully tightened the white screw nut. You will now have a fully pressurised boiler.
• If you find the needle is now indicating a number above 2 bar you may need to bleed your radiators to release further pressure from the system. 

• Your boiler gauge should read between 1-2 bar. If your boiler gauge reads under 1 bar you will need to increase the water pressure by repressurising it.
• There are two blue handles located underneath the boiler.
• Turn both blue handles a quarter of a turn to the left to increase the pressure to the boiler.
• Look at the boiler pressure gauge reader and once the gauge shows a reading of above 1 bar, turn both blue handles back the right to close the valves.
• Once complete your boiler should be working efficiently again.  

You can find helpful videos about this type of boiler from the Ideal Heating YouTube channel.