What Pressure Should My Boiler Be?

Here at ADI Leak Detection we often get asked – what should the pressure be on my boiler? In this blog post we aim to answer that question for a range of circumstances including for different Boiler manufacturers such as Bosch & Vallient.

Maintaining the correct pressure is an integral part of keeping your heating & boiler running smoothly and without issues.

If this crucial element goes wrong you can find yourself without heating or hot water – not ideal in the depths of winter. Left untreated, your boiler could stop working altogether

What Pressure Should Your Boiler Be

What Is Boiler Pressure?

Before we go any further, it is important to ascertain exactly what we mean by ‘boiler pressure.’ In the simplest terms, this refers to the pressure of the hot water which runs through your boiler and throughout the sealed central heating system of your home.

Water pressure, on the other hand, refers to the pressure of water which comes through your taps, and the two are linked. If your boiler pressure is too low, you could risk your system cutting out – this prevents your central heating from working.

How Do I Know My Boiler Pressure?

Boiler Pressure Guage (Analogue)

Most boilers will come with a small dial either on the boiler or near the boiler, and this is the secret to reading your boiler pressure. In most cases, your boiler pressure guage will have two zones – red and green, and a dial. If the dial hits the red zone at either end, your boiler pressure is too high or too low; in either case there is a problem which needs resolving.

If the boiler pressure is too low then it could be because of a leak on the pipework of your heating system or a fault with the boiler itself.

If your boiler pressure is too high then you can reduce the pressure yourself in most cases and keep your heating working.

What Should Boiler Pressure Be When Heating Is On?

As your central heating kicks into life, your boiler will also heat up – you will be able to see this clearly by taking a look at the pressure gauge. As the heating runs, the pressure increases and builds up – this is a result of water expansion, as the water in your system travels through pipes and radiators.

In a normal working boiler, the pressure will not rise by more than 0.3-0.5 bars, and so the overall pressure should read between 1.5 and 1.8 bar – anything outside of this range when your heating is on could indicate a cause for concern, – often an issue or fault with the pressure release valve or expansion vessel – and it is usually a good idea to have this checked out.

What Should My Boiler Pressure Be When It Is Cold?

When the boiler is cold,  your boiler pressure will usually hover between 1 and 1.5 bar (14.50 – 21.75 PSI) , with most manufacturers opting for a middle point of 1.3 bar (18.85 PSI)

It is important to note that each boiler make and model may have their own variations, and so it is a good idea to consult the owner’s manual before panicking if yours seems different to this average.

Common boiler manufacturers such as Worcester Bosch, Ideal Boilers & Vallient Boilers genrally follow the rule of thumb when it comes to boiler pressure. Baxi Back Boilers use a wider pressure range.

Boiler Pressure Guage

What Do I Do If My Boiler Pressure Is Too High?

If you notice your pressure creeping up towards the red zone, you can reduce the pressure quite easily – this can also happen if you have overdone it, topping up the pressure. Water can be bled from the radiator without too much stress – all you need is a radiator bleed key, a container to catch the water, and a towel.

How To Reduce Your Boiler Pressure By Bleeding Radiators.

  1. Insert the bleed key into the gap, and slowly open the valve.
  2. Once it starts to dribble water, you can close up using the same key, and check the boiler pressure.
  3. If it is still not right, simply repeat the process until you reach the desired result.

In some cases, you may accidentally drain too much from the system, and this can cause the pressure to drop. If this is the case, you can top up the system using the filling loop.

What Do I Do If My Boiler Pressure Is Too Low?

Leak Detection Company For Low Boiler Pressure

As we mentioned, there are some occasions where your boiler pressure drops, and this can also be seen in the dial – or  in the form of a F1 error code on an Ideal Boiler. A loss in pressure can be due to over-bleeding of the radiator – this tends to be easily fixed – or may be a symptom of a more serious problem, which is best addressed by a professional.

You may notice that your boiler pressure continues to drop even after a fix, and this can be a sign that there is a leak somewhere in the system. If this is the case then call ADI Leak Detection on 0800 731 3843 – we are the experts in tracing hidden water leaks.

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