Even if it only happens for a few hours, losing hot water in your home can become a real nuisance. Particularly in the morning, with people fighting to use the shower, losing hot water can lead to significant delays, which cost time and money. As a homeowner, it is imperative to know what you can do to restart your hot water supply and understand the key checks to make before bringing in an engineer to fix it.

Do Some Checks

It is important to first clarify the scale and cause of the issue. Start by checking the hot water supply to different areas of your home to see if it has stopped entirely. Sometimes, localised plumbing issues can prevent water running from a single tap. However, if you are not receiving hot water though any of your taps then it’s more likely to be a boiler or system problem.

Have you had a power cut?

If your hot water has stopped working entirely, then the next step is to check whether your water, gas and electricity supply are all functioning as normal. If they aren’t, try resetting them to see if that resolves the issue. It is possible that you may have had a power cut to your home and if so, this could have caused the fuse box to trip. A power cut may also have meant any heating controls or timers have lost pre-programmed settings so it is important to check those too as they may not have prompted the boiler to turn on when expected. If this is the case, then it’s simple to fix, however if it is not – you’ll need to look for other solutions.

Is my boiler turned off?

The next step would be to check that your boiler is still switched on and whether it is displaying a fault light or code. If so, you can look to reset it following the manufacturer’s instructions. However, if the boiler is correctly switched on and displaying no sign of a fault code, you will need to take some further steps to identify the issue.

Know your boiler

Once you are confident that your hot water problem is being caused by a boiler fault, it is handy to know what type of system you are operating. With this knowledge, you can make a few final checks before having to call in a Gas Safe Registered engineer:

Combi Boiler

If you have a combi boiler and have followed the basic steps above but still aren’t receiving hot water then it is most likely an issue with the boiler unit itself.

Separate Boiler and Hot water tank or Cylinder

If you operate a separate boiler and hot water tank or cylinder, it is worthwhile checking if your programmer is set correctly and the cylinder thermostat is turned up. Some people with hot water cylinders have an electric immersion heater fitted for use as a back-up. If so, you can turn this on to get hot water until you call out an engineer. However, this is only a short-term solution as the use of an electrical immersion heater can quickly become costly.

Condensing Boiler

If the issues are occurring during a particularly cold weather spell and you have a condensing boiler, then check if the condensate waste pipe is frozen. If it has, then it is possible to thaw it without calling in a Gas Safe Registered engineer. There are a number of YouTube videos available online, which can provide guidance on how to do this safely.

Low Pressure in the Boiler

If you have a sealed system boiler in your home, checking the pressure is another advisable step, as if it is too low it may prevent the boiler from working. If your boiler has a pressure gauge, check to see if the level is between 1 to 1.5 bar. If the pressure is below that it is likely to be the cause of the issue. Once again, this is something that can be corrected without professional help; however it is important to follow the manufacturer’s guidance on how to safely restore the pressure to an appropriate level. For some additional assistance on boosting boiler pressure, we have our own quick video guide, which can be accessed here.

What to do before brining in an Engineer?

If your hot water has now been off for an extended period and none of the above steps have resolved the issue, you will need to call a Gas Safe Registered engineer to make further tests. We would also advise checking thoroughly around the boiler unit and pipework for any visible leaks as these will necessitate a far quicker response time from an engineer. Finally, once your boiler is back up and running, check to see whether it is due for a service as keeping on top of your annual boiler services will help to prevent against any more nuisance breakdowns in the future.


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