If you’ve noticed that a boiler is suddenly letting out steam, it’s most likely coming from the boiler relief valve, also known as a pressure relief valve. This is will affect any central heating or heating systems.

The boiler relief valve is likely discharging steam and/or hot water for one of the below reasons:

• The pressure levels inside the boiler are too high
• The valve itself is faulty and needs replacing

Here’s what to do if you are in need of fixing your boiler or combi boiler. At Anglo, we stock a range of boiler relief valves that are perfect for the job.

Confirm that the boiler relief valve is the issue

Before you start your repair, you’ll want to make sure that it’s actually your boiler relief valve that’s letting out steam.

Important - the boiler relief valve is the only place on a boiler that should ever let out steam.

If you find that the steam is coming from elsewhere on the boilers, likes most likely that there is a leak instead which is allow the steam to escape.

So, if the steam is coming from the boiler relief valve, then continue to determine what you should do to fix the problem.

Check the pressure levels of the boiler

If the boiler relief valve is letting out steam as a safety measure, the boiler pressure levels are over 30 psi (pounds per square inch). When this level is hit the boiler relief valve is designed to automatically discharge hot water/steam when pressure, to reduce the psi safely. If you can hear a loud humming noise, it’s likely that the boiler’s pressure levels are too high.

How to check your boiler pressure levels:

• Locate the pressure gauge which is typically located on the side of the boiler.
• Read the pressure level. These levels should be around 12 to 15 psi. If the levels are significantly higher, this is most likely what’s forcing your pressure relief valve to open and discharge steam.
• If the levels are too high, bleed the radiators. You should do this immediately to reduce the pressure incase of a rupture.

If the levels are normal, replace the boiler relief valve

The boiler relief valve is most likely faulty and needs to be replaced if the boiler pressure levels are normal (12-15 psi).

Over time, hot water and steam will continuously escape via the valve if sediment from water have had time build up in the valve and prevent it from sealing properly.

Choose from our selection of Boiler Relief Valves and you’ll be ready to carry out the repair.

If you would like any more information regarding our valves or need to speak with us directly regarding any technical specifications, you can contact us on +44 (0) 208 979 0988 or fill out our contact form and we’ll get back to you asap.