Is Your Boiler Losing Pressure?  Read The Professional’s Guide To Boiler Pressure Loss Before Calling A Plumber…

Has your heating suddenly broken down on you?

Is there a lack of hot water right when you need it most?

Have you started to notice your boiler losing pressure?

All of these signs can be indicators that something is going wrong with your boiler, and this is a job best tackled as soon as possible. Your boiler is a central hub in your home, and sometimes a simple issue can cause significant issues including a lack of heating or hot water, and a sudden drop in boiler pressure.

Water Leak Detection Team

From leaks to broken parts, radiators to faulty valves, there can be a number of reasons behind a sudden loss in boiler pressure; understanding these leads to faster identification of the problem and, in turn, a speedy solution which leaves you with a working boiler in no time – leaving boiler pressure issues in the past!

Here at ADI we are specialists at Central Heating leak Detection & Trace and Access services – so if a leak is the cause of your boiler pressure loss then we are here to help. 

If the problem with your boiler pressure is not related to a leak then we hope to point you in the right direction via the content on our informative plumbing, heating & leak detection blog.

Navigate To Help Faster Within This Article…

What Is Boiler Pressure and Why Does A Leak Matter?

What Pressure Should Your Boiler Be

It is a term commonly heard; we have all had an expert (or not so expert) head in, nod sagely at our boiler and explain that “it’s the pressure.” Most of us will respond with a “oh, of course!” and return a nod in favour, without the faintest idea what is actually going on.

Let’s start with the boiler: it’s primary job is to heat up cold water. This then flows through the maze of pipes leading to radiators all across your home. In order for this to happen successfully and for you to settle down toasty warm, the pressure needs to be stable.

In the simplest terms, boiler pressure refers to the pressure of the hot water which is currently running through your sealed central heating system. This is a different concept to water pressure – as the name suggests, this refers to the pressure of water coming out of your taps. For total balance and peace, you need to ensure that your boiler has an exact balance of water and air – and this can be as tricky as managing the in-laws at Christmas. Too little pressure, and your system will not have enough water to fill the radiators. Too much, and the build up can be…interesting.

Common Causes of Boiler Pressure Loss

In most cases, the issues occur when you have low boiler pressure. If this happens, the system can completely cut out, leaving you with zero pressure in the central heating, and preventing your heating from working. In the majority of modern boilers – known as ‘combination boilers’ – the pressure is kept even and maintained by a filling loop, which connects to the cold water pipe.

It is pretty easy to determine when your boiler has lost pressure; in most cases you will lose heat, and sometimes hot water. You can also take a look at your boiler, and the tiny dial will tell you everything you need to know. If it has fallen below one: you know you have an issue.

Understanding the most common causes of pressure loss can help you get closer to tackling the issue for good. There are usually one of two reasons behind a sudden drop in pressure:

Leaks From Your Boiler Or Heating System

Boiler Pressure Guage

Leaks are one of the most commonly reported causes of a drop in pressure, and these unwanted annoyances have a tendency to sneak up on you unnoticed. They can remain in your house, hidden and rent-free, until you notice that there is a problem. Despite their sneakiness, there are nonetheless a few tell-tale signs that you have been invaded by leaks. If you notice any damp patches around the boiler, or around radiators and pipes, there could be a deeper issue. Having to continually top up the water pressure is another clue that there is a leak somewhere, and you should get the boiler checked out by a professional (preferably one from ADI, not that we’re biased).

Faulty Expansion Vessel

Expansion Vessel & Boiler Pressure Gauge

Expansion vessels are another common culprit; this is usually identified by your pressure hitting the 3 bar and continuing to rise while the boiler is heating up. If the vessel fails, the water which is expanding has nowhere to go, and pressure will continue to rise – pressure increases with temperature. If this happens, the aforementioned pressure relief valve will expel any excess pressure from the system until it is safe. When the system cools, the water lost will show as a drop in pressure. Checking this is simple. Run the heating at full pelt, and see if the pressure gauge rises. If the dial keeps moving, get in touch with us as soon as possible – this is definitely not a job for an amateur.

Faulty Pressure Relief Valve

Bleeding Radiators Causing Low Pressure

A faulty pressure relief valve can be another common reason for a loss of pressure. This valve will either be found inside the boiler, or as part of an external unit – as a basic rule, if you immediately pick it out, it is internal. These little guys release the excess pressure if too much builds up, and the dial exceeds three bars. If the valve fails, you will notice water leaking from the system, as well as a much lower pressure.

Radiator Bleeding Key

Bleeding your radiators naturally leads to a drop in pressure, due to the very nature of the task. When you bleed the radiator, the air is released, and the pressure in the boiler is lowered, leaving you facing frostbite.

Why Are Leaks Such A Problem?

As we mentioned, leaks are one of the primary issues which can wreak havoc on your boiler. As well as being extremely annoying, leaks can cause a range of problems in your home, including:

  • Higher bills – water leaking means you are using more of it, so you can expect sky-high bills. We are pretty sure you would rather spend your money on more interesting things, so get that leak checked out.
  • Frostbite – well, maybe not actual frostbite, but you will certainly be pretty cold if there is no central heating in the dead of winter.
  • Rust – if your central heating system has a leak, it will need to be constantly refilled to compensate. Over time, this can result in oxidation, leading to rust and damage on the inside of your pipes and radiators.
  • Damage to your home – if the leak is inside the home, such as a tank, an underfloor heating system, a water pipe or the central heating system, it can cause significant damage to your interiors. Walls and floors can be completely ruined, and this can be expensive and time consuming.
  • Unwanted visitors – leaks cause damp, and this invites a multitude of unwanted visitors into your home, including insects, bugs, mites and other pests. These guys thrive in a dark, damp setting, and can cause a huge amount of damage to the structure and security of your home.
  • Health issues – damp can also increase your risk of contracting respiratory conditions and other illnesses, including asthma.

Can I Check My Own Boiler Pressure?

It is pretty easy to find the pressure on your boiler; once you have the know-how, you will be checking like a pro. Most boilers will come with a pressure gauge, and this indicated high or low pressure with red sections on the dial.

If this dial moves into one of these areas, you know something is wrong, and it is time to call in the pros. Super modern options will likely come with a digital gauge, which will flash if there is an issue.

In most cases the pressure will drop to below one bar, and this is a red flag that water has been lost from the system, and needs to be replaced. In a combination boiler, the filling loop will usually take care of this – unless you have a leak. If the dial heads to high pressure, you may be able to bleed a radiator to get things back under control.

Be wary here though, high pressure can be dangerous, and you could land yourself in hot water – in every sense of the word.

How To Repressurise A Boiler

In some cases, you may be able to restore optimum pressure to your boiler with just a few simple adjustments and tweaks. It is a good idea to check out the website dedicated to your particular boiler before commencing – this will give you a better idea of where things are and what they look like before you get started. Some sites may also offer their own ‘how to’ guide for repressurising that particular model.

Wait, back up there…repressurising?

Relax, repressurising is just a fancy term for adjusting the pressure, and this is achieved by allowing more water to enter the system from the water mains supply. This is added via the filling loop – all boilers will have one of two options, either built in or external. The basic process is almost the same for both options:

  1. Switch off the boiler, and allow it to cool – this is perhaps the most important stage, and should not be skipped or rushed.
  2. Double check the boiler to ensure that both ends of the filling loops are securely attached, and in good condition.
  3. Open both of the valves. This allows the cold mains water to enter the system, and should be audible if you listen closely.
  4. Keep an eye on the pressure gauge; when it hits the 1.5 bar, you are good to go.
  5. When the dial hits 1.5, close both valves
  6. Switch the boiler back on, and hit the reset button

When To Call In A Professional Leak Detection Company Regarding The Loss Of Boiler Pressure


Leak Detection Company For Low Boiler Pressure

It is important to note that while a simple repressurising of the boiler is usually a fairly painless task, there are some fixes which are absolutely not suitable for a beginner. The key is knowing when you are beaten – in the majority of cases, you are far better off calling a professional, and letting us take care of the hard work. This has a number of advantages; you will stay safe, get to keep your eyebrows, and can kick back with a brew while watching someone else do all the work – always an advantage. It also means that you will be less likely to encounter the same problem six months down the line.

Leaks in particular are an area which may need an external pair of eyes. Here at ADI, our team is highly skilled and qualified in detecting and tackling leaks – the clue is literally in the name. Our experienced team are Central Heating Leak Detection Specialists, have the equipment and knowledge to trace a leak on your heating system causing your boiler pressure loss.

Your boiler is an integral aspect of the smooth, comfortable running of your home – without it, the entire ambiance and environment can be ruined (not to mention your mood if you are forced to stay in a freezing cold house in the depths of December). This is one relationship it is essential to nurture; staying on good terms with your boiler is the secret to success, and this means addressing any needs and ongoing maintenance as it is required.

If Your Boiler Is Losing Pressure Slowly & You Suspect A leak Then Call Us Now On 0800 731 3841