020 8016 2350

Why does my Vaillant boiler keep losing pressure?


For the past decades, Vaillant boilers have been trusted by homeowners in the United Kingdom for their high-performance and efficient hot water and heating solutions. Vaillant boilers are trustworthy because their energy consumption is very low, and every model comes with a ten-year guarantee. Subsequently, if you already have a Vaillant boiler installed at your home, you must know how efficient it is. Alternatively, this blog was put together by our team at Boiler Solutions to help you understand and find an answer to the question, why does my Vaillant boiler keep losing pressure?

Also, if you have ever wondered about the importance of going for a boiler service London, then check out our homepage. Coming back to our Vaillant boiler, low-pressure or sudden leaks are some of the most common issues faced by boilers with continuous use. Therefore, if your boiler keeps losing pressure, it is high time to get it checked by an expert. Or you can solve the problem by yourself if you have enough knowledge of boiler functions. Find out more about our Boiler Services in London.

Boiler Servicing and Maintenance

We believe that your safety and the safety of your home is of utmost importance during a boiler service or any other gas appliance-related work. Our customer-first approach is what has allowed us to build up a stellar reputation over the last decade. The only way to ensure that your boiler or appliance is functioning efficiently and safely is with regular maintenance and professional servicing, which are usually carried out annually. There are a number of reasons to get a yearly service.


Why does my Vaillant combi boiler lose pressure?

Vaillant combi boilers are the most common choice for homeowners. This is because they require small spaces to get installed and can supply hot water for the whole day without needing a storage tank. Vaillant combi boilers are saviours, especially during harsh winter seasons, but what happens when you notice a loss of pressure? Before we get to the point, do check out our blog about low boiler pressure symptoms. Low pressure is a common issue in boilers, and there can be two main reasons behind this, which is:

  • A leak is the primary cause of pressure dropping and the boiler malfunctioning. This leak can appear in a radiator valve or other parts that carry water.
  • The second most common reason is air or water release from radiators. This may occur during or after bleeding them.

A technician can quickly fix these two common reasons behind low pressure in boilers. But, before setting an appointment, you must discover the exact reasons for air releases or water leaks. If you still cannot find leaks, look for damp patches around radiators, flaking or discolouring pipes, and water stains. So, if you have asked yourself, why does my Vaillant boiler keep losing pressure?, then we will keep reading to learn more.

Your Local London Boiler Company

We cover all of London - from Wandsworth to Westminster and Brixton to Bromley and everywhere in between. If you’re looking for a boiler service in London then you’ve come to the right place. Boiler Solutions is one of London’s leading plumbing and heating companies.


Featured videos


What do I do if my boiler keeps losing pressure?

Pressure loss in a boiler is a widespread issue. Almost 99% of the reasons are leaks in radiators and pipework. Even after fixing these issues, what can you do if your boiler keeps losing pressure? You need to consult an expert. Before moving to the solution, it is crucial to focus on the significant problems that lead to low pressures:

  • A Faulty Expansion Vessel – System and combination boilers are ideal for homes and come with an expansion vessel. Sometimes, this vessel may have faults resulting in low boiler pressure.
  • Leaks In Radiator, Radiator Pipes, And Boiler – Leaks are the most common reason behind low pressure in the boiler. To discover them, you must always check the radiator pipes and the surface of the radiators. You can seek experts’ help to find internal leaks such as boiler leaks.
  • A Leak In The Pressure Release Valve – Pressure release valves are the safety device of a boiler that usually prevents the system from extreme pressure build-ups. Sometimes, a leak in the pressure-release valves can result from low pressure.
  • Bleeding Radiators – If you sometimes bleed your radiators, the pressure gauge may indicate low pressure just after you have finished the process. This is a common reason behind low pressure and fixing this problem is easy.

Can boiler pressure drop without a leak?

Although not the most common issue witnessed by homeowners, sometimes, your boiler pressure may drop even when there are no leaks in radiators or pipework. This situation can give rise to many worries because the problem is not evident, and finding its solution can be a bit challenging. Sometimes, when there is a leak in the internal system, particularly a boiler leak, or a minor fault in the inner parts of the boiler, a situation of constant low pressure arises.

With regular use, the boiler parts get loosened or corroded; this may further lead to leaks and faults and, as a result, affect the boiler pressure. Finding out the faulty part of a boiler is not your cup of tea. Hence, when you consult technicians, they can detect and deal with these problems efficiently. With regards to leaks, why not read up on topics such as how to fix a leaking boiler pipe.

Get the help of an expert

When you have discovered the reason behind the pressure gauge indicating low readings, it becomes easier to find a solution. Each of these problems above has a solution that can either be resolved by you or an expert. An expert will ensure you do not face such issues again soon. Sometimes, when a situation of low pressure rises suddenly, you may try to fix it by switching off the system first.

Then, you can proceed with filling up the boiler through a filling loop. The next step must include opening the filling valve and waiting until the pressure gauge again indicates a reading of 1.5. You may close the valve after regular pressure readings and see your system running smoothly again. If the problem is not fixed after this simple step, it is time to consult an expert. We hope this blog has enabled you to understand the question, why does my Vaillant boiler keep losing pressure?