Boiler pressure is too high? Find out why and how to lower it  

Your boiler is treading a fine pressure line for your boiler every day. Not too high, but not too low. Just right. What happens if your boiler is able to get off the track? What is the reason and what can be done to fix it?


A nurse who wears a tightly contracted armband won’t be required to check the pressure of your boiler.

If it’s high enough, your boiler will notify that, however not via WhatsApp or via your gauge for pressure in your boiler.

 …or it’ll fall apart.  

In this article we’ll discuss the main causes for boiler pressure being excessive, and also how you can lower your boiler’s pressure.


The first thing you need to consider is: Top 12 (most frequent) boiler issues .

What exactly is boiler pressure? Why is it relevant when it’s high?


Boiler water pressure is the ratio of air and water within the boiler’s system (basically in the pipes and parts).

To allow your boiler to circulate hot water through the pipes inside your house whether it’s to shower, bathe or heating your radiators, the pressure in your system must be enough.

Low pressure in the boiler is not a good thing.

High pressure in the boiler is not good.

In the case of pressure, how high can be too high?


If you didn’t purchase your boiler from Home Bargains, it’s going have a gauge for pressure at the front that can be recognized as an amalgamation of an Casio watch and a speedometer on the Ford KA.

Most pressure gauges for combi boilers will show the pressure between 0-4 bar.

Did you know that if the boiler pressure is constantly high levels, it could be a sign of bigger issue?

What is bar? We don’t know however it appears to function as a measure.

The ideal pressure for boilers typically marked with the reassuring color – is anywhere between 1 and 1.5 bar.

Anything less than 1 bar and you’re dealing with an appliance that’s 

The pressure gauge on the boiler reads 2.5 bar or more? This is too high.

3-4 bar can be funny. It’s likely that your boiler has shut off as a safety measure.


Boiler pressure readings as high, but only when the heating is turned on?

A pressure gauge for a combi boiler reading above the 1.5 mark, even though the heating is running at full capacity it is most likely because of the demand for water being put on the boiler, so it’s unlikely to cause any concern.

In this case the reading of 1.5 to 2.5 bar could be considered normal. A constant reading between 3 and 4 bar is something to discuss with your regional Heating engineer.

If your boiler is showing high pressure readings frequent on a regular basis, or is more than 10 years old, and has seen its fair share of problems it is time to look into a replacement.

Boilers must be checked at least once per year, and especially when they’re oil or gas-based, Check out our guide to find out How often should you keep your boiler in good condition?

Here are the most frequently-cited reasons the pressure in your boiler is too high (and the best way to repair the problem):


It might be free, or it might cost money.

How to Reduce Boiler Pressure

Take these steps to lower the pressure on your boiler:

#1 – There is too excessive water entering the system.

The most frequent cause for this is if you’ve recently filled (repressurised) the pressure of your boiler following it’s been suffering from low pressure.

How do you check:
Take a look at the needle readings on your trusted boiler pressure gauge. If it’s reading above 1.5 bars (when your boiler has been turned off) the pressure in your boiler is high.

If you’re experiencing pressure-related problems on a all often it could be the right the time to look into a replacement.

How do you repair:
It is necessary to remove some of the water off the system.

This can be done by  bleeding your radiators. do not worry, they won’t suffer any discomfort.

If you’re interested to find out how much a brand new boiler is going to cost, fill out this short questionnaire to find out no cost.

To flush your radiator it will require an keys for your radiator or something that is able to turn comfortably and safely the valve located on the top the radiator.

After you’ve used this tool and found the radiator valve, slowly twist the valve clockwise. The valve should initially sound like the air escape prior to water beginning to leak out of the valve. Allow a little bit in water out of each radiator, making sure to check the pressure after each one.

Continue doing this until your gauge of pressure is back in the beautiful green zone.

If you’ve noticed an insatiable thirst to bleed it is recommended that now seek out help. Do not ever cut anything with the force of a pulse.

Did you let out too much? But don’t fret, you could simply add pressure once more.

Cost to repair:
Time, patience, and PS0.00.

NOTE: If you have an older boiler, and are suffering from lockouts and low water, it is possible to think about whether you might have an damaged heater.

Want to find out which boiler manufacturer did the worst? Find out with our review of the most dangerous boilers.

#2 – Parts of the boiler that are not functioning properly


Some of the components at risk are the boiler’s release valve for pressure, diverter valve or the filling loop, which could be detected by an untrained eye.

What to look for (pressure release valve) The PRV is a straightforward device to let water out when the boiler is the pressure. It’s a copper pipe that is typically located on the exterior wall, behind the boiler.

It’s bent and it almost seems embarrassed by its own self.

If the pipe you’re using is constantly dripping , the PRV isn’t satisfied with something, and you need to contact an engineer to look the boiler. If you’re receiving none of your hot water coming from the boiler the failing component may be the reason.

How do you check:
It is the metal pipe that flexes underneath your boiler with one or even two taps in black. Make sure whether the taps are closed to ensure that they don’t continuously increase the pressure in your boiler.

How do fix:
If the taps to fill the loop were left open Make sure that they’re shut. If this is an issue it’s best to get an specialist to examine the situation.

Cost to repair (Pressure release valve):
PS100 – PS350

Cost to repair (Filling loop):
PS80 – PS150

It’s important to note that age isn’t just an age-related number for boilers. If your boiler is more than 10 years old and is not functioning it is time to look at repair costs in comparison to the price and benefits of a brand new boiler installation.

Most common errors for boilers operating at high pressure:

Worcester Bosch boiler pressure too high

Common errors:
E9, A1, 224V, 1065B, 2970B

Apply for (boiler version):
Worcester Bosch Greenstar 25i, Worcester Bosch Greenstar 30i, Worcester Bosch CDi, Worcester Bosch CDi Classic, Worcester Bosch CDi Compact, Worcester Bosch CDi Highflow.

Vaillant boiler pressure is too high

Most likely errors:
F.12, F.74, F.75, S.41

Application for (boiler type):
Vaillant EcoTEC, Vaillant EcoTEC Pro, Vaillant EcoTEC Plus, Vaillant EcoMax, Vaillant ecoFIT.

Ideal boiler pressure not enough

Common error codes:
F1 Ideal boilers are those that communicate with users in English and display only written messages regarding pressure issues, which can be… perfect.

Apply for (boiler version):
Ideal Logic, Ideal Logic Plus, Ideal Vogue, Ideal Vogue Max, Ideal Mini, Ideal Isar.

Do you have a boiler that is leaking and it’s also leaky?


If your boiler is more than the level of a London finance broker at noon on a Friday and leaks similar details from a Julian Assange laptop, then your boiler may have been weakened by the pressure it’s been subjected to.

In time, boilers under strain from the pressure will create cracks and seal breakages in pipes and valves, which can cause leaks.

It’s likely that you’re at minimum going to require the parts replaced. And typically it’s cheaper to invest in an repair for your boiler.

Below are top five reasons for the leaky boiler..

What boiler do you prefer? Below are some of the top combi boilers as well as the most efficient system boilers..

Does your boiler make loud noises? Find out the reason with the loud boiler guide.

Is high boiler pressure dangerous?

In the majority of instances, there is not always.

The majority of boilers stop working through a security device known as the PRV (Pressure Release Valve) or even break down when the pressure of your boiler is too high for too long.

The worst-case scenario for boilers that suffer from high pressure would be an malfunctioning boiler as well as a carpet that has soaked.

If your pressure issue isn’t solved using a DIY fix, it is recommended to contact an engineer from the boiler industry immediately.

To figure out the price an upgrade to your boiler will cost make use of our online calculator. Check out our top boiler manufacturers list to discover which ones are suitable to heat your home. This financial boilers guide will also assist when you want to purchase your boiler on a monthly basis.

High pressure, the most important conclusions:

  •  Chinese  
  •  Indian  
  •  Pizza  

 But seriously…  

  •  Make sure you regularly check the pressure gauge and watch out for high and low pressure  
  •  If you are experiencing low pressure, top it up with the loop for filling  
  •  If you notice a slight increase in pressure, even when the boiler is off you should flush the radiators prior taking on a expensive repair  
  •  Do not perform any other task on a boiler. Call an engineer if you have any doubt.  
  •  Relax, pressure issues that are minor aren’t that bad  
  •  Consider a deep clean i.e. an pressure flush to clean the boiler from sludge an issue that could cause corrosion and blockages.  

In the event that your appliance is more than 10 years old, it will need repairs of up to PS150. You may be at the very beginning of the end. So, check for new boilers that have warranties that are longer than the one in this article and payments broken into pieces which are small enough to take them all in.


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