If your boiler isn’t working then don’t panic just yet as you may be able to fix it yourself or you may also need a Gas Safe registered heating engineer, however, the most common reason for a boiler not to work is low pressure or a frozen condensate pipe in winter.
Other common problems are no gas or electricity to the boiler, faulty thermostats or controls or if your boiler is old may be breaking down and, unfortunately, even the best combi boilers have an off day, so let’s see if we can help!
Boiler not working – Problems you can fix yourself and how to do it
Here are some of the most common boiler problems that you can fix yourself and these quick fixes could save you money on call-out charges to a gas engineer when it is not needed.
If you are unsure, then it may be worth paying, but hopefully, the reason your boiler is not working is one of the following reasons, and you can mend it yourself.
If your boiler is old, you need a new one and luckily, you can find out how much a new boiler cost online now.
Check that your boiler is switched on at the mains
Before doing anything, ensure that your boiler has power to it as this may embarrassingly be caused by accidentally switching it off, a fuse blowing, or a power cut.
If there is no electricity to your boiler, it won’t work, therefore if this is the case, you may have just found your problem, but if not, and assuming your boiler is switched on and has gas running to it, then the following fixes can work right away.
Ensure your gas and utility bills are up to date, or your prepayment meter is topped up
If for whatever reason, you aren’t up to date with your gas and electricity payments, then suppliers can cut off your supply, and this is a worst-case scenario, so you should be aware that this is happening. If your not you must get in contact with our supplier right away.
You have the right to have heating in your home at all times, so hopefully, this is just a quick fix for you.
Quick boiler fixes for common reasons why your boiler won’t work
These are some of the easiest things to do to get your broken boiler back up and running before calling a heating engineer and all of these tips should get your boiler back working if it is the reason it is not firing up.
If these fixes don’t work, you will need to speak to a plumber and check out the other reasons why further down the page.
Boiler Pressure too low
This is the ideal problem to have in terms of a quick fix for a boiler not working. All you have to do is top up your low boiler pressure, and your boiler will start working again.
Once the boiler is at least in the correct range, it will start up again if this is the issue.
How to top up boiler pressure
To top up the low boiler pressure you need to find the filing loop underneath your boiler. These will have two valves very close to each other, which you need to open at the same time.
You also need to see your pressure gauge so that when you get to 1.5bar or within the green area on some boilers, you can close the valves.
If your boiler has turned off, switch it back on or reset it, and it should start to fire up properly, however, if the pressure starts to drop again repeatedly, then you have a leak somewhere in the system, and you will need to call an engineer.
See how to repressurise a Worcester boiler here – these most popular boiler brand in the UK for the past decade.
Frozen condensate pipe
A frozen condensate pipe is a massive reason why people’s boilers don’t work in winter as the excess water that your boiler is producing is freezing when it is getting outside and stopping any more water from escaping, causing your boiler to shut down.
Fixing a frozen condensate pipe
- Hot water poured over the condensate pipe outside your home will fix this problem for you instantly.
- Do not call out an engineer and waste money before checking this issue if it is freezing outside.
- It is a 2-minute job!
Boiler thermostat and controls not connected
Assuming that your boiler is switched on but central heating not coming on, then you may need a new thermostat, or the batteries may need changing.
This is a quick and simple fix you can do yourself. If you change the batteries and it doesn’t work then your thermostat may be broken, or the connection at your boiler is faulty.
You should see a green light on the receiver at your boiler if it is connecting.
If it is, then it is unlikely to be your thermostat. Smart thermostats will tell you if they are not connected too.
Reasons your boiler may not be working that required and heating engineer
These are the situations where your boiler can be fixed but only by a Gas Safe registered heating engineer.
All the following will mean that the heating engineer has to open up the boiler to investigate and check the boiler over.
It may also mean parts need changing or fixing, which are more technical than just topping pressure up.
Boiler leaking water and not turning on
If there is water leaking from your boiler fast or slow, then it is likely that you are going to need to call a plumber to fix it and you possible may have no water from your tap at all.
Your boiler may stop working during this time, it may turn itself off, or it may be on but not providing heating or hot water.
There are numerous reasons, such as corrosion, broken seals, or broken heat exchangers.
Check out our boiler leaking water guide if you want to know more about water leaks.
Problems like this can cost between £100 and £500, so it may be worth considering a new boiler.
The boiler won’t turn on, and electricity is switched on
If you are confident that your electricity supply is working and your gas is flowing then you may have a severe internal problem. This could be with the electronic parts inside, such as a broken circuit board or fuse that has blown internally.
If this is the case, expect costs of around £200 to fix at least.
If your boiler is really old, it may be worth thinking about getting a new boiler.
Find out how much a new boiler costs here.
The boiler switched on but no hot water.
If your boiler is switched on and showing a green light to say that your thermostat is connected, and when you turn your taps on there is no hot water, you likely have a faulty diverter valve stopping hot water from being delivered to your taps.
This is a job for a heating engineer and will require your old diverter valve to be taken out and replaced with a new diverter valve.
Again, if you have an old boiler, you need to decide whether it is worth replacing or getting a new combi boiler.
The radiators are not getting hot, but the boiler is working.
If your boiler is on, getting warm, and providing hot water to your taps, but your radiators are still cold, then you may have a blockage in your radiators or a faulty diverter valve.
The best thing to do is check the radiators that get hot water from your boiler first. If they are warm but the ones in other rooms aren’t, then you have a blockage and will need either a chemical system flush or a power flush.
These do not require a new boiler, but the blockage needs to be removed so that it doesn’t get in your boiler.
Boiler not working error codes – what do they mean?
If your boiler is not working, you may get an error code and here are some of the most common boiler error codes for boilers in the UK so you can diagnose the problem quickly and easily. If they persiste, why not consider a boiler replacement instead as it may work out cheaper in the long term?
Viessmann Error Codes
These error codes relate to the Vitodens 050, Vitodens 100 and Vitodens 111-w boilers, and more.
| Frozen condensate pipe | F4 EE |
| Burner blockage | F1 |
| Low Pressure | Check Gauge |
Worcester Bosch error codes
Error codes for Worcester Bosch boilers you may come across for their Greenstar range, such as the Worcester 4000, Worcester 8000, and Worcester 2000 boilers
| Frozen condensate pipe | D5 EA |
| Heat Exchanger Issue | A1, CE 207, H07, 224V, 1017W, 2970B |
| Pilot light is not firing up | EA, F7, FA, EA227, F7 228, FA306 |
| Heat Exchanger error | 2963 B, 2964 B, 2966 B, 2967 B |
| Internal Fan Fault | C6, T2, C6 215, C7 214, C1 264 |
Vaillant Error Codes
These error codes relate to Vaillant and the Vaillant ecoTEC boiler range
| Frozen condensate pipe | F28 and F29 |
| Pressure too low/high | F.24, F.12, F.22, F.73 |
Ideal Error Codes
Ideal error code relating to the Ideal Logic boiler range
| Frozen condensate | LF,F2,L2 |
| Fan not working | F3 |
| Low water pressure | F1 |
| PCB (circuit board) error | F9, L9, F8, L8 |
Baxi Error Codes
Baxi error codes, including the Baxi 600 range
| Frozen condensate pipe | e133 e28 |
| CB (circuit board) error | E100, E167, E168, H.02 – 02, 4-5 Green Flashes |
| Pressure too high/low | E28, E119, 117, 118, 119 |
| Pilot light error | E128, E129, E384 |
The combi boiler is not working, do I need a new boiler?
Suppose you have fixed your boiler or called an engineer out, great but if you think your boiler may be on the blink or breaking down, you may want to get a quote for a new boiler.
You could get a quote just to see how much a new boiler costs, including installation, just in case.
It may save you money in the long run, cost less than you think or save you money on repeat call-outs.
