Common Problems With Central Heating

Problems with your central heating can be serious, particularly when it’s cold outside, so it is helpful to know how to identify what‘s wrong. Sometimes you will be able to fix it yourself, but in other cases you will need to call out a qualified engineer.

Radiator Problems

Sometimes the problem only affects one or some of your radiators, rather than the whole system. Radiator problems can be easier to solve than issues with the boiler. One possibility is that the valves on those radiators are closed or faulty, so you should check this first to avoid any unnecessary work.

If one of your radiators still isn’t working or if a radiator is only heating up at the bottom, it might need to be bled to get rid of air that is trapped inside. You can do this after leaving the system to cool down. You will need to open the valve at the top of the radiator with a key. The air will rush out first. When it is followed by water, you should shut the valve again.

The radiator could also be blocked with scale, rust or sludge, particularly if there are cold patches in the middle or at the bottom. If you have an open-vented system you can add sludge remover to the tank that supplies the radiators, which is separate from your hot water tank. If you have a closed system, you will need to get an expert in to flush it.

If the radiators are working in one part of the house, but not in another, it is probably because the pump is failing or broken. It is particularly common for the radiators upstairs to be affected while those downstairs are still working, because it takes more power for the pump to move the water up to the higher floor. It could also be due to a build-up of limescale, which can be tackled by adding a de-scaler in the same way as the sludge remover.

If none of your radiators are working, then you may have a problem with your boiler.

Boiler Issues

If there is a problem with the boiler, it will usually need to be fixed by a trained engineer. The exception is when the pilot light has gone out, as you should simply be able to relight it using the manufacturer’s instructions.

Some of the common issues that you may need help to solve include:

  • Problems with the power or gas supply
  • Leaks, often caused by cracks or broken seals, which need to be fixed quickly to prevent corrosion and more damage
  • Stuck pump or valve, which needs to be freed
  • Broken pump needing to be replaced

Strange Noises

A noisy central heating system could have several different causes, which can often be identified by the type of sound that you hear.

  • Banging is often caused by air in the system, which can be removed by bleeding the radiators. It could also be caused by scaling, which can be treated with de-scaler.
  • Creaking sounds, which may be accompanied by banging, can be caused by the pipes pressing and knocking against the walls or floor as they expand and contract. Ensuring the pipes are securely fixed in place or slightly enlarging the holes through which they pass can solve this problem.
  • Humming noises are usually caused by the pump, even if they seem to come from the radiators. The pump may could be fitted too loosely or it may need to be turned down if it is moving water too quickly through the system.
  • Rumbling from the boiler is known as kettling. It is caused by a build-up of sludge or limescale, which should usually be treated by an engineer. However, similar noises can happen if the thermostat is set too high, which can cause overheating. Turning it down could solve the problem.

Problems with the Controls or Timers

Some of the most common and easily solved problems with central heating relate to the controls. It is important to check that the timer and thermostat are both set correctly if the heating isn’t coming on as expected. If this doesn’t fix the problem, it could be that these components need replacing.


If you require a plumber in Woking to fix a problem with your central heating system please contact us for more information or for a quotation.