Boilers: Boiler maintenance tips Open-vented boilers

Checking the flame

Gas flame inside the gas boiler

You can check the flame through the pilot window on older boilers

On older boilers – typically those more than 20 years old – you should be able to check the pilot light. There will normally be a see-through window that allows you to see the flame. If your boiler is combusting properly the flame should be blue, if it has turned yellow, you’ll need to call out an engineer.

If your pilot light goes out, consult your boiler manual to find out how to turn it back on again. Typically, this will involve holding down the reset button and clicking the ignition switch.

After the flame reappears, you’ll most likely need to keep the reset button held down for at least 30 seconds before releasing it. If this doesn’t work after a few attempts, you’ll need to call out an engineer.

No heating or hot water

On an open-vented system, if the pilot flame is lit, but you don’t have any heat or hot water, you may find the ball valve is stuck in the feed and expansion tank.

Typical symptoms include upstairs radiators being cold, and no air or water coming out of them if you try to bleed them. The circulation pump may also be particularly noisy.

If you go to the feed and expansion tank (normally next to your cold water tank) and find it is empty, try moving the ball valve up and down. The valve should start working again, and the feed and expansion tank should start to fill up.

Save money with a new sealed system

Older, open-vented non-condensing boilers take air in from inside your home, whereas newer, sealed condensing systems take air directly from outside. This means that a newer sealed condensing boiler will normally take in cleaner air and be better at retaining energy.

A new sealed condensing boiler will be at least 25% more efficient than an older non-condensing type.

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