My boiler pressure is too high, how do I fix it?
Whenever there is an issue with a boiler, it causes a lot of worry and stress. Dealing with a boiler when its pressure is too high can be one of those moments. However, understanding why this happens and knowing how to address it can alleviate much of the stress associated with boiler maintenance.
Boiler Pressure Norms – the Guidelines
Your boiler’s pressure is crucial for its operation. Typically, the pressure gauge on your boiler should read around 1 bar when the heating is off and no hot water is being used. This is considered the standard low-pressure setting. When the heating is on, the pressure should increase slightly, ideally sitting between 1.5 and 2 bars. Most boilers will have this optimal range marked in green on the gauge, indicating the pressure is set correctly.
Causes of High Boiler Pressure
High boiler pressure usually occurs when the heating system is in use, as the water inside the boiler expands upon heating. This expansion causes the pressure gauge to rise. Thanks to the expansion vessel built into modern boilers, these fluctuations in pressure are generally well-managed. However, if the pressure gauge reads above 2 bars, it indicates that the pressure is too high.
Reducing Boiler Pressure
If you find your boiler’s pressure is higher than it should be, you can take the following steps to bring it back to its correct setting:
Turn Off Your Boiler: Start by switching off your boiler and allowing the system to cool down. This is crucial for safety and accurate pressure reading adjustments.
Check the Pressure Gauge: Locate and read the pressure gauge. A reading above 2 bars indicates that the pressure is too high and needs adjusting.
Close the Filling Loop/Relief Valve: Ensure that the filling loop or relief valve, which might have been left open accidentally and caused the increase in pressure, is securely closed.
Bleed Your Radiators: Air trapped in the heating system can also contribute to high pressure. Bleeding your radiators can release this trapped air, helping to reduce the pressure. Use a radiator key to open the bleed valve on each radiator until water, instead of air, comes out.
Recheck the Pressure: After bleeding the radiators, revisit the boiler pressure gauge. Ideally, the pressure should have returned to the correct setting. If not, you may need to repeat the bleeding process or investigate further issues.
Should your boiler pressure remain high after following the above steps, it may point to a more complex issue, such as a need to repressurise the expansion vessel or a fault with the filling loop. These are not DIY fixes and require the expertise of a Gas Safe registered engineer.
The Pressure in My Boiler is Too Low
Conversely, if your boiler pressure is too low (below 1 bar), it could indicate a need to bleed your radiators or a leak in the system. For guidance on repressurising your boiler, consult a professional or refer to detailed guides on managing low boiler pressure.
Continuing Problems with Boiler Pressure?
Managing your boiler’s pressure is key to its efficiency and longevity. By understanding what causes fluctuations and knowing how to rectify high pressure, you can ensure your heating system remains in top condition. However, when in doubt or faced with persistent issues, it’s always best to consult with a professional to safeguard your home heating system.