If you're experiencing issues with your boiler, then it could be down to your boiler pressure. We've got easy to follow information and advice on how to resolve common issues.
What to do if your boiler loses pressure
If you have noticed that your heating system has become less efficient, or your pressure gauge has dropped into the red, then you will need to top up your boiler pressure.
How to repressurise your boiler
Topping up your boiler pressure is a simple fix and can be carried out without a heating engineer. First of all, identify what sort of filling system you have by watching this video, then visit our playlist and follow the instructions on our videos to show you how its done.
External Filling Loop
You'll be able to identify if you have an external filling loop, because there'll be two valves; one from the mains cold water and then a second valve which is connected to the heating system.
- Attach the hose to each side of the valve and open the mains cold tap.
- Open the second tap which allows water in to the heating system
- Watch the pressure rise and stop once the bar reaches just about one and turn off both taps
- Remove the taps from the hose, be mindful that there will be some water dripping out
Internal Filling Loop (Keyed)
Locate the key this will usually be on a flap underneath the boiler or it may have been provided you as part of the installation
- On the front right hand side you'll notice an open black port and this is where the key fits
- You'll notice a picture of an open padlock and a closed padlock and on the white key there is an arrow on the shaft, align the arrow with the open padlock as you push it up into the open port
- Turn the key and watch the pressure rise to just over one bar
- Turn the key back to the open padlock and remove. Be mindful of any water dripping
Keyless Internal Filling Loop
A keyless filling loop is easily identifiable, as you'll see a blue lever at the bottom of your boiler
- To repressurise the system with the keyless filling link simply pull down the blue lever
- Once the pressure has increased to over one bar, release the lever
Time to upgrade?
Your boiler is at the heart of your home. It provides comfort on cold nights, and hot showers before a hard day, so having a reliable boiler is a must.
Get ready for winter and replace an older, G-rated boiler with a modern, A-rated boiler with full heating controls could help you save up to £500 a year on your gas bills*.
*Source EST 2026 July 2026. Estimated figures based on installing a new A-rated condensing boiler with a programmer, room thermostat and thermostatic radiator controls (TRVs) in a gas heated detached GB home, from an older, G-rated boiler with a programmer and room thermostat. Savings will vary depending on the size and thermal performance of your home. https://energysavingtrust.org.uk/advice/boilers/
Upgrade your boilerGet your boiler winter-ready
Our winter checks can help you prepare your home and your boiler for winter, to make sure there is less chance of your boiler breaking down and keep your heating running smoothly.
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