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Heating » No hot water, no heating » Refill your central heating boiler

Central heating boiler refilling

If the pressure in the boiler is below 1.5 bar, you should refill the boiler. Follow these 10 easy steps to do this yourself. 


  1. Connect a hose to a water tap, e.g. a kitchen or bathroom tap. Sometimes you need to remove the tap faucet to fit this. 
  2. Fill the hose with water to prevent air in the heating system. 
  3. Connect the open end of the hose to the filling valve of the boiler. 
  4. Turn the heating off using the main plug. 
  5. Check if both ends of the hose are connected properly. Gently open the water tap.
  6. Open de filling valve with a quarter turn on the tap.
  7. Watch the pressure bar and stop filling when it reaches 1.8 on the bar pressure gauge. 
  8. Close both the valve and the tap.
  9. Remove the hose carefully and hold in a horseshoe shape to avoid leakages before you empty in to the sink
  10. Turn the boiler back on and bleed the radiators.

Filling valve

The filling valve of your heating system is usually located near the boiler.  Screw the metal cap off, connect the hose and tighten the flow control device with an allen key connect the other end of the hose to the tap which will now run water into the boiler.