Simple steps to lowering your boiler pressure
Before you get started, you’ll need a radiator bleed key and some tissues, or a hand towel, to catch any drips.
- Turn your heating on – this will warm up your radiators and build pressure in your system.
- Check your radiators – if you can hear gurgling sounds and your radiators have cold spots, you’ll need to bleed those specific radiators.
- Turn your heating off – if you don’t, you’ll be at risk of scalding yourself and getting hot water on the floor.
- Get the tissues ready – when you bleed a radiator, some discoloured water will come out and will need to be caught before falling on your carpet/floor.
- Open the radiator bleed valve – using your radiator bleed key, insert it into your bleed valve, this is often found at the side of a radiator and looks like a round hole with a square inside. When you insert the key, you’ll feel them lock together, turn the valve anti-clockwise – you’ll hear a hissing noise which is the hot air escaping, so be careful.
- Bleed your radiator – a quarter-turn of the valve will be enough; don’t turn it too far or else water will come rushing out. Hold the radiator valve open until the air stops coming out and water starts to drip out - this means you’ve successfully bled a radiator.
- Seal the valve – turn the radiator bleed valve clockwise to tighten, making sure not to overtighten. Repeat the above processes on all the radiators that need bleeding.
- Check the pressure on your boiler – once you’ve bled your radiators, check your boiler’s pressure gauge to see if your system needs to be re-pressurised. If it’s between 1.0 - 1.5 bars then you’re all done.
- Adjust boiler pressure - if your boiler pressure is too low then you need to manually increase the boiler pressure, this could be with a central filling loop that’s connected to your boiler. Find out what make and model your boiler is, then go to the manufacturers' website, they'll have a walkthrough explaining how to increase pressure for your exact boiler.
Your boiler pressure should now be back to the recommended levels.
How to increase boiler pressure
Each boiler is different and will have different ways to increase the pressure, so it's very important to find out which boiler make and model you have. When you know it, proceed to the manufacturer's website and they'll likely have a blog/video that will explain how to increase your exact boiler's pressure.
Here's the most common way to increase boiler pressure:
- Switch your boiler off and let it completely cool.
- Find your boilers filling loop. This is a flexible hose found underneath your boiler with a small valve at each end, make sure both ends of the hose are secured and attached to the two valves.
- Use the valves handles on either side, turn them clockwise and open the valves. This will then allow the cold mains water into the system, and you'll hear it filling up the system.
- The pressure will now increase, so pay attention to the pressure gauge until it gets to the 1.5 bar mark. You'll then want to start closing both valves by turning the valves counterclockwise.
- Turn the boiler back on and reset your boiler if necessary.