Common boiler faults and how to fix them

If something goes wrong with your boiler, you could be left with a hefty bill for a boiler repair or have to spend hundreds, if not thousands, on a new boiler altogether.

Whilst this can be worrying for many, not every boiler fault has to lead to a large cost. Some issues are easily diagnosed at home and may not require a gas engineer, for example bleeding your radiator or adjusting your boiler pressure. We have written down some common boiler faults and how to fix them.

Is your boiler leaking water?

This could mean that your boiler pressure is either too high or too low. Have a read about how to repressurise your boiler here.

Alternatively, it could indicate a pipe leak. If you see any pipework surrounded by water, dry it up. Once you’re sure that the leak is coming from there, tighten the seals slightly to stop the leak.

It’s important to note that leaks can indicate something serious, so it’s best to call a Gas Safe engineer to fix the issue. Thankfully, all of our engineers at Swale Heating are Gas Safe registered. so that’s one less thing to worry about.

Is the water not hot enough even though the heating is on, or are your radiators not heating up even though your hot water is working?

If your hot water is working but your heating isn’t, or vice versa, this could indicate an issue with the diverter valve.

Commonly found in combi boilers, diverter valves open and close to control direct hot water to either your radiators or taps and showers.

The best thing to do in this situation is to call a Gas Safe registered engineer to fix this issue. As your boiler is a gas appliance, performing technical maintenance on this can be extremely dangerous.

All of Swale Heating’s engineers are Gas Safe registered. Feel free to contact us today.

Do you have a leaking radiator valve?

One of the most common problems when it comes to radiators, is a leaking radiator valve and it can be a total pain.

Firstly, you need to figure out exactly where the leak is coming from. If there’s water near the valve, it could be coming from the radiator itself, the valve or the pipework.

Dry the area of water and check to see where the leak is. Remember to check each part: TRV or lockshield valve (depending which side the leak is on), the pipework and the radiator body.

Usually, the leak is coming from the TRV valve. You will need some PTFE tape to help fix this issue. Follow these steps:

  1. Drain the leaking valve – remember to have something like a bucket or bowl to catch the running water
  2. Turn off both the TRV and lockshield valves
  3. Catch any remaining water from the valve
  4. Using a spanner, unscrew the union nut. This is found at the bottom of the valve
  5. Open the bleed valve to get rid of anymore water
  6. Wrap the valve tail in PTFE tape to stop further leaks
  7. Put the valve back on the radiator by re-tightening the union nut
  8. Re-open both the bleed and lockshield valves
  9. Once the radiator has refilled itself with water, check again for any leaks
  10. If no more leaks, close the bleed valve

Is your boiler not working at optimal performance? Or maybe there’s a strange smell?

If your boiler isn’t quite right, it could be a sign that the heat exchanger isn’t working properly.

The heat exchanger is a vital part of the boiler that converts energy to gas. This heats up the water, which is then fed through to the rest of the system. After the heated water circulates, it returns via the heat exchanger, which reheats it. This process continues until the desired room temperature is met.

Over time, the heat exchanger can become faulty due to wear and tear. Limescale build-up is a real issue, especially in areas with hard water, which can cause the heat exchanger to not work to its full potential.

This build-up of limescale can cause the system to overheat. If the water reaches boiling point too quickly, this can cause kettling and whistling noises.

Another issue that can harm the heat exchanger is a build-up of sludge and debris in the central heating system. This is due to dirt particles being transported round the system via the water. It can affect your pipework, radiators and the boiler itself.

One thing you can do is flush out your central heating system. There are a few heating system cleans that can be performed to flush out dirt and debris.

Other issues that may arise due to a damaged heat exchanger include:

  • A yellow pilot flame
  • A water leak
  • A carbon monoxide leak – this can be life-threatening and must be seen to straight away. If you think this is the case, call the Gas Emergency Services on freephone 0800 111 999
  • A strange smell – again, this can be very dangerous so it’s best to call a Gas Safe engineer immediately

If any issues arise, the best thing to do is to contact a Gas Safe engineer. A qualified engineer will be able to inspect and clean the heat exchanger, and will tell you whether it needs replacing or not.

Do you have no hot water?

Finding out that you have no hot water when you turn the shower on can be infuriating.

There could be many reasons why this is happening, and it may not always be because of your boiler.

For example, there may be a problem with your fuse box. Check to see that your switch hasn’t tripped out and cut the power to your heating system.

Next, check the thermostat. If it’s on too low, your boiler may not switch on to heat the water.

Another issue could be the timer. If you’ve recently had a power cut, this can affect the timer. Check that this is set at the right time and reset if not.

Now, check the boiler:

  • Check to see if the pilot light is on. Relight the flame if it’s gone out. If it keeps blowing out, this will need to be checked by a qualified engineer
  • Check the boiler pressure
  • Reset the boiler if you’re able to. Sometimes, the boiler’s reset button is placed inside the boiler’s casing. In which case, a Gas Safe engineer will have to do this for you
  • Check the pipes – maybe your pipes have frozen. You can thaw frozen pipes by pouring hot, not boiling, water over them
  • If all else fails, turn the boiler on and off again

Does your boiler keep switching off?

If your boiler keeps switching off at random times, this could be because:

  • The boiler pressure is either too low or too high – if the dial shows that your boiler pressure isn’t between 1 and 2 Bar, you may need to repressurise it.
  • There is trapped air in the system – if you also feel cold spots on your radiators, you may have air trapped inside them. If so, you can bleed your radiators
  • Your thermostat may be faulty – a simple fix such as changing the batteries could solve this issue
  • There may be sludge and debris build-up in the system – if your central heating system is making funny noises, not heating up properly or your boiler keeps switching off, have a look into a heating system clean
  • The condensate pipe may be frozen – the condensate pipe is a pipe that transports gas wastage into the outside air. All condensing boilers have one. If it’s frozen, this can cause the boiler system to switch off. Simply pour hot, not boiling, water over the pipe to unfreeze it

We hope that this guide has helped you figure out the potential problem with your boiler and how to fix it.

We also have more helpful guides for if your radiator is noisy or your boiler displays a fault code.

The best way to prevent an issue with your boiler is to get it checked every year. Whilst this isn’t a legal requirement, unless you’re a landlord, it’s a good idea to get it serviced annually to give you peace of mind that everything is safe and in full working order.

To be extra prepared, you can also sign up to one of Swale Heating’s boiler service plans to ensure that you are not landed with a hefty bill for if something goes wrong.