Do I have the right boiler pressure?

Your boiler is made up of many different parts. These parts, or components, all work together to create a central heating system that performs to a high standard and provides your home with heat and hot water whenever you need it.

When each part of your central heating system works together in harmony, everyone’s happy. However, something seemingly small going wrong or a fault being experienced can throw your whole system into chaos. It’s important to maintain all the parts of your system that you can, in order to keep it working effectively. Sometimes you won’t know something has gone wrong until your boiler breaks down, but there are some things that can indicate a problem early on. By addressing these straight away, you may be able to save yourself from your boiler experiencing downtime and you experiencing a hefty repair bill.

Here at Bog Standard Plumbing, we’ve seen every boiler issue there is to see. One common issue experienced by homeowners is a problem with the pressure of their boiler. We’ve written this guide to explain more about boiler pressure, how to check it and, potentially, how to resolve any issues as simply as possible.

If you need any further help, don’t hesitate to contact us. 

How can I check my boiler’s pressure?

Checking the pressure of your boiler is the first important step in establishing if it could be the root of a problem with your central heating system. To do this, you need to locate it on your boiler. The pressure gauge is usually fairly easy to spot, in most cases at the front of your unit. It will appear a little like a small clock face, with a needle indicating where the pressure lies.

The needle should sit in the green zone, resting between bars 1 and 1.5 if the pressure is correct. If it is above 1.5 your pressure is too high, if it is below 1 then it is too low. 

What to do if your boiler pressure is too high

When there is trapped air in your radiators, it can affect the boiler’s pressure, causing it to rise. This can be simple to resolve if you feel confident, by bleeding your radiators.  

Bleeding your radiators with a radiator key or a screwdriver should relieve the pressure levels in your boiler. Importantly, it should also help your radiators give out more heat, as when air is trapped in them they don’t heat fully, often failing to warm your rooms.  

After carefully bleeding your radiators, check the boiler pressure again, which should have dropped to within the correct range.

What to do if your boiler pressure keeps dropping

If the pressure of your boiler is too low, it will need repressurising, but it’s important to understand why it keeps dropping, as it probably signifies that there is a fault with your system. If the pressure drops because something else is faulty, repressurising it won’t solve the problem as it will keep happening. 

If your boiler pressure is below 1 bar, the best thing to do is to contact a Gas Safe registered engineer who can fully investigate and advise on next steps.

Boiler pressure can drop for the following reasons:

  • Because of a leak. If there is water escaping from your system it can cause the pressure to drop. Even if you spot just a small amount of water coming from your boiler or any pipes then you will need to call a Gas Safe registered heating engineer.
  • Due to a damaged or broken part. The pressure relief valve in your boiler is connected to the pressure, and if this wears out or experiences a failure then your pressure can drop. You won’t be able to check the pressure relief valve yourself so, again, a Gas Safe registered heating engineer will need to be called. 

Correcting low pressure with the filling loop

There is a filling loop on some modern boilers, that allow you to repressurise your boiler should it drop below the normal level.  Only attempt this if you have the manufacturer’s instructions for repressurising, and make sure you fully understand them and feel confident to carry it out yourself.  If the pressure drops again after you repressurise then be certain to contact a trusted Gas Safe registered heating engineer who can properly investigate. 

Trusted boiler repairs in Birmingham, Stourbridge, Wolverhampton & Dudley

The team at Bog Standard Plumbing are trusted by homeowners across Birmingham, Stourbridge, Wolverhampton and Dudley. If you’re having  trouble with your boiler’s pressure then we can help. We’re Gas Safe registered, reliable and professional, so don’t hesitate to get in touch.  

You can call us on 0330 113 2248, email us at or complete our short online contact form