If you’ve noticed that your boiler pressure keeps dropping, you’re not alone. This is one of the most common heating issues homeowners experience, especially during the colder months when boilers are working harder.
While it’s normal for boiler pressure to fluctuate slightly, regularly needing to top it up could indicate an underlying problem that should be investigated. If you are not confident in doing so yourself and you live in the Kent or Bromley area, contact us.
What Is Boiler Pressure?
Boiler pressure refers to the amount of water circulating within your central heating system. Most modern boilers operate best when the pressure gauge reads between 1 and 2 bar when the system is cold.
If the pressure drops too low, your boiler may stop working correctly and could display a fault code.
Common Signs of Low Boiler Pressure
You may have low boiler pressure if:
- The pressure gauge is below 1 bar.
- Your radiators are not heating up properly.
- The boiler keeps switching itself off.
- A fault code appears on the boiler display.
- You regularly need to repressurise the system.
Why Does Boiler Pressure Keep Dropping?
1. A Leak Somewhere in the Heating System
Even a small leak can gradually reduce the pressure within your heating system.
Check for:
- Damp patches around radiators.
- Water beneath pipework.
- Leaks around radiator valves.
- Signs of moisture near the boiler.
Small leaks can sometimes go unnoticed for months.
2. Recently Bled Radiators
If you’ve recently bled your radiators to remove trapped air, it’s normal for the boiler pressure to reduce slightly afterwards.
The system may simply need repressurising.
3. A Faulty Pressure Relief Valve
The pressure relief valve is designed to protect your heating system if the pressure becomes too high.
If the valve becomes faulty or gets debris trapped inside it, it can allow water to escape unnecessarily, causing pressure loss. This usually means a boiler repair is required.
4. Expansion Vessel Problems
Modern combi boilers contain an expansion vessel which helps accommodate changes in water volume as the system heats and cools.
If the vessel loses its charge or develops a fault, the boiler may repeatedly lose pressure and require professional attention.
5. A Fault Within the Boiler
In some cases, the issue may be inside the boiler itself. Components such as seals, heat exchangers, or internal pipework can occasionally develop leaks that lead to pressure loss.
Can I Repressurise the Boiler Myself?
Many modern boilers can be repressurised using the filling loop located underneath the appliance. This is usually done by opening two taps.
However, if the pressure repeatedly drops after topping it up, there is likely an underlying fault that needs investigating.
Simply adding more water to the system does not fix the root cause.
When Should You Call an Engineer?
If you find yourself topping up the pressure more than once or twice a year, it’s worth having the system inspected.
Persistent pressure loss can lead to:
- Reduced heating performance.
- Higher energy bills.
- Increased wear on boiler components.
- Unexpected boiler breakdowns.
Need Help with a Boiler Losing Pressure?
At Clean Deal Boiler Services, we regularly diagnose and repair boilers that are losing pressure around Kent and Bromley. Whether the problem is caused by a leak, faulty valve, expansion vessel issue, or another heating fault, we can quickly identify the cause and recommend the most effective solution.
If your boiler pressure keeps dropping, contact us today to arrange an inspection from our experienced Orpington-based engineer and get your heating system back to reliable operation.
