A boiler with stable pressure is essential for keeping your heating system working efficiently. If you’ve noticed a pressure drop, it could indicate an underlying issue that needs attention. Low boiler pressure can lead to poor heating performance and even system failures if left unresolved. Here’s a look at some common causes and what you can do to fix them.
1. Leaks in the System
One of the most common reasons for a drop in boiler pressure is a leak somewhere in the system. This could be in the pipework, radiators, or even within the boiler itself. Small leaks may go unnoticed, but over time, they can cause a significant loss of pressure. If you suspect a leak, check for damp patches, rusted pipes, or water stains around your radiators and boiler.
2. Bleeding Radiators
If you have recently bled your radiators, you may have inadvertently caused a pressure drop in your boiler. When air is released from the system, it can lower the overall water pressure. This can usually be resolved by topping up the pressure using your boiler’s filling loop.
3. Faulty Pressure Relief Valve
The pressure relief valve is designed to release excess pressure if it gets too high. However, if the valve is faulty or has been triggered too often, it may allow water to escape, leading to a continuous drop in pressure. A professional heating engineer can check whether the valve needs repair or replacement.
4. Expansion Vessel Issues
Modern boilers are fitted with an expansion vessel that helps maintain consistent pressure. If this component is faulty or loses its charge, the system may struggle to hold pressure properly. This usually requires expert inspection and maintenance.
5. System Filling Issues
Your boiler relies on the right level of water to function correctly. If there’s been an issue with filling the system—such as a partially closed valve or incorrect pressure setting—the pressure may drop. Topping up the water using the filling loop can often resolve the issue.
How to Repressurise Your Boiler
If your boiler pressure is too low, you may be able to fix it yourself by following these steps:
- Locate the filling loop, usually a silver, flexible hose beneath the boiler.
- Open the valves slowly to allow water to enter the system.
- Watch the pressure gauge and close the valves when it reaches the recommended level (typically between 1 and 1.5 bar).
- Restart your boiler and check if the pressure holds.
When to Call a Professional
If you continue to experience pressure drops despite topping up your system, it’s best to call a professional. Persistent issues could indicate a more serious problem, such as internal component failure or a hidden leak. At JWD Heating & Plumbing, our expert team can diagnose and repair any boiler pressure issues quickly and efficiently.
A well-maintained boiler ensures your home stays warm and energy-efficient. If you need assistance, contact us today—we’re always happy to help!