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Everything You Need To Know About Boiler Pressure

Does your boiler pressure gauge show you everything you need to know about boiler pressure? Well, perhaps not. It's normal for your boiler pressure to rise as it heats, and to fall as it cools. Boiler pressure dials generally indicate low and high boiler pressure with green and red colour coded markers.

On most boilers – combi boilers and traditional boilers – the pressure gauge is either on the front of your boiler or behind a control panel. Older boilers pressure gauges were usually underneath as part of the pipework. Your instruction manual will guide you.

Low Boiler Pressure

Some boilers do lose pressure slowly over several months of regular use. Modern boilers need very little attention. An annual service is usually is all that is required. You should be able to know that the boiler pressure is correct by the temperature of the water circulating.

Boilers need to be topped up perhaps once or twice a year. However, a sudden pressure drop is a sign of a system leak. Drips of water around the base of the boiler are the most obvious signs. Sometimes, the pipes may be at fault, so it's wise to look for patches of damp along with all the pipework.

High Boiler Pressure

High boiler pressure with the needle in the red zone is typically due to overfilling. A fault in the system could also cause the problem. If your boiler is shutting down or won't switch on, you have a problem. Call a Gas Safe engineer. Proper early diagnosis and resolution is the best course of action.
If your boiler pressure is high, leaks can develop. Keeping the correct boiler pressure is both safe efficient for hot water and warmth. If you at all concerned call a professional Gas Safe heating engineer to look at your boiler for you.

Common problems with Boiler Pressure

When there's no heating or hot water, it is usually because the heating system boiler pressure is wrong. Your radiators won't warm up properly unless the boiler pressure is in the right zone.

Low boiler pressure isn't dangerous but will cause your heating and hot water system to fail. Sometimes, small leaks happen very slowly drip by drip over time until the pressure in the system is just too low to operate. Removing air from radiators (called bleeding radiators) while good for your heating eventually, it can cause an immediate boiler pressure drop and require a top-up. You can usually re-pressurise your boiler yourself, once you've turned it off first. Once the pressure is back up and stays up with no apparent signs of leaking water, you can only then power the boiler back up.

High boiler pressure will cause the system to shut down. It's not usually dangerous if your boiler has a pressure relief valve (PRV). The boiler pressure valve lets water escape, generally down a small pipe that runs to the outside. Most systems shut down automatically when boiler pressure is too high.
Boiler pressures that keep rising to the red zone are best left to a Gas Safe Engineer to diagnose problems, and restore your hot water quickly.

If your boiler is in need of repair or you require a boiler replacement, Boiler Breakdowns can help. We have a team of heating engineers and boiler specialists based across the whole of London, from North London and East London to South West London. For more information call: 020 8819 6867 or fill in our contact form.

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