Why Is My Boiler Losing Pressure? Common Causes and Solutions
If you’ve noticed that your boiler keeps losing pressure, you’re not alone. Low boiler pressure is one of the most common issues homeowners face, and it can lead to inefficiencies in your heating system, cold radiators, and even a complete system breakdown. Understanding why your boiler is losing pressure can help you diagnose the issue before it becomes a bigger problem.
In this blog, we’ll explore the most common reasons for pressure loss in boilers and what steps you can take to fix it.
What Does Boiler Pressure Mean?
Boiler pressure refers to the amount of water circulating in your heating system. It’s measured in bars, and your boiler’s pressure gauge will typically display the pressure level. For most systems, the ideal pressure is between 1 and 1.5 bars when the boiler is cold.
If the pressure drops below this range, you may notice your heating isn’t working as efficiently, or your boiler may stop functioning altogether. But why does this happen?
Common Causes of Boiler Pressure Loss
- Leaks in the System
One of the most frequent reasons for boiler pressure loss is a leak somewhere in the system. This could be a small, slow leak from a pipe or radiator valve that isn’t immediately noticeable. Over time, the constant water loss reduces the pressure in your boiler, causing it to drop below optimal levels.
How to spot it:
- Look for visible signs of water leakage around radiators, valves, or pipes.
- Check underneath the boiler and around pipe connections for drips or dampness.
- If you can’t find a visible leak, it may be hidden in the walls or underfloor heating pipes, requiring professional leak detection.
- Faulty Pressure Relief Valve (PRV)
Boilers are fitted with a pressure relief valve (PRV) to prevent the system from becoming over-pressurised. If your boiler’s PRV is faulty or damaged, it may release water when it shouldn’t, resulting in a loss of pressure.
How to spot it:
- Check if there’s any water escaping from the PRV discharge pipe (usually located outside your property).
- Look for puddles or dampness around the boiler’s external wall where the pipe exits.
- Bleeding Radiators
Bleeding your radiators can help remove trapped air and improve heating efficiency, but it can also cause the pressure in your system to drop. This is because when you release the air, some water escapes, leading to a loss of pressure.
How to spot it:
- After bleeding your radiators, check the boiler’s pressure gauge. If it has dropped below 1 bar, you’ll need to repressurise the system.
- Expansion Vessel Problems
The expansion vessel in your boiler helps to maintain pressure as the water heats up and expands. If the expansion vessel is faulty or has lost its charge, it won’t be able to regulate the pressure properly, causing it to drop.
How to spot it:
- Check if the boiler pressure rises dramatically when the heating is on and then drops when it’s off.
- A faulty expansion vessel often needs to be replaced by a professional.
- Airlocks in the System
Airlocks can occur when pockets of air become trapped in your heating system, preventing water from circulating properly. This can cause inconsistent heating and pressure drops.
How to spot it:
- Listen for unusual gurgling or banging noises in your radiators or pipes.
- If certain radiators are cold at the top, it could indicate trapped air.
How to Fix Boiler Pressure Loss
- Repressurise Your Boiler
- Most boilers have a filling loop that allows you to add water back into the system and increase pressure. Follow the manufacturer’s instructions to do this safely.
- Check for Visible Leaks
- Look for any signs of water around radiators, pipes, and the boiler itself. Small leaks can often be fixed by tightening valves, but larger or hidden leaks require professional help.
- Call in a Professional
- If you can’t locate the issue or your boiler continues to lose pressure after repressurising, it’s best to contact a qualified engineer. Persistent pressure loss may indicate a larger problem like a damaged expansion vessel, PRV, or hidden leaks in your heating system.
How Specialist Leak Detection Can Help
If your boiler is consistently losing pressure and you’ve ruled out visible leaks, there could be a hidden leak in your system. At Specialist Leak Detection, we use advanced leak detection methods like thermal imaging, acoustic testing, and tracer gas to locate even the smallest leaks without causing damage to your property.
Our team of skilled engineers can quickly identify the source of your problem, helping you avoid costly repairs and preventing further damage to your home. Whether it’s a central heating leak, a faulty pipe, or an underfloor heating issue, we have the tools and expertise to get your system back to normal.
Don’t let a hidden leak cause unnecessary stress. Contact Specialist Leak Detection today for a fast and reliable solution to your boiler pressure issues!
