Central Heating Troubleshooting
There could be a number of reasons why your central heating or hot water isn't working. You can fix several problems yourself, avoiding a callout and - if you're a HomeCare® customer - possibly saving you money. Try these tips first:
- check the gas, electrical and water supplies to the appliance are turned on. It's surprising how easily they can get accidentally switched off
- check the thermostat is turned up and the clock timer is on
- some boilers have a pressure gauge showing system water pressure, this usually needs to be at around 1 bar, read more about system pressure
- got a system with a permanent pilot light? Check that it hasn't gone out - this is a very common problem with older appliances
- try putting your heating on maximum for a short while to see if you can get it back into action
- have the clocks gone forward or back? Your clock programmer might just need adjusting to the right time
- has there been a power cut recently? Your heating clock programmer may have returned to its factory settings when the power came back on. Test the central heating by setting it to come on in 15 minutes time - if that works, simply re-enter your preferred settings
- do you have a customer-operated reset switch (not one that needs you to remove any casing)? These are usually found on the front of modern boilers: check your user manual to see if it needs resetting
- try turning the electrical supply to the boiler off and on - the switch is usually near the boiler or in the airing cupboard. This might reset your boiler and resolve the problem
- could you have frozen pipes? In periods of long, cold weather, the condensate pipe of your boiler can freeze. See my pipes have frozen
- are other gas appliances affected? If so the problem is bigger and you need to Book a callout
For open vented system boilers
(You have this type of boiler if it has a small black tank. You'll usually find these in the loft.)
Has the ball valve float in the feed and expansion cistern got stuck?
(this is usually a small plastic or steel tank situated in the loft)
If so, when your water system falls to a certain point, system water can't circulate. If you can safely and easily get into and move around your loft, check to see if the ball valve is stuck (usually indicated by no or low water in the cistern). Gently move the ball float valve arm to free it - do not use force. This may solve the problem.
For sealed system boilers or combination boilers
(You have this type of boiler if it doesn't have a cistern that looks like a smaller version of your cold water cistern.)
- has the system pressure dropped? This is sometimes caused by water leaks, and can stop the boiler from working properly:
1. check the pressure gauge - this should be set at 1 bar. A red indicator needle sometimes shows the position set when the boiler was installed.
2. look in your user manual to see if you can re-pressurise the boiler yourself - you can also find instructions on the rear of the control panel. But if your boiler panel needs tools to remove it, do NOT touch it: Book a callout instead.
- View More: British Gas Central Heating Troubleshooting
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/Solution/?solutionID=1549
My radiator(s) isn't working
First check if the problem is with one radiator, or with all your radiators.
Problem with just one radiator
Try turning the radiator valves to maximum (turn the taps anticlockwise). If this doesn't work you may have to bleed the radiator to remove any air in it. This may need to be done if you've recently decorated or had to remove/isolate the radiator.
How to bleed a radiator
- a radiator bleed key - these can be bought from a DIY shop
- a dry cloth
- to wait until your central heating system is completely cold
- For safety, turn the central heating and hot water off.
- Place the dry cloth under the radiator to catch any water that may come out.
- Find the square bleed screw at the top of the radiator on the side or back.
- Insert the bleed key and turn it slowly anti-clockwise (by no more than 2 turns as the screw shouldn't be removed completely) until you hear a hissing noise.
- Wait until the hissing stops and you start to see small amounts of water coming from the bleed screw.
- Retighten the screw but be careful not to over-tighten it.
- Got a combination boiler? Check the pressure gauge on the front of the boiler. If it's below its normal setting, you'll need to add water to your boiler. See your boiler manual on how to do this.
- You can now put the heating back on.
Problem with all your radiators? See my central heating is not working.
Still not working? If the problem continues, book a callout.
- View More: British Gas My radiator(s) isn't working
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/Solution/?solutionID=2731
My central heating is leaking
First check where the leak is coming from and whether it's somewhere other than the central heating - look at the seal around the bath or the roof, for instance.
Confirmed it's the central heating that's leaking? To limit the damage, turn off your heating and your cold water stop tap, then book a callout.
Not sure how to turn off your heating? Check your user manual.
- If you have an open vented system - with a cistern in the loft - it can take a bit of time for the leak to stop, unless the system is completely drained. So don't worry if the leak doesn't stop immediately, it soon will.
What could be the cause?
A possible cause of the leak is a punctured pipe, especially if you've had some DIY or building work done in your home recently. To see if you're covered under your HomeCare® agreement, check your terms and conditions.
- View More: British Gas My central heating is leaking
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=2746
My pipes have frozen
To try unfreezing the boiler condensate pipe yourself, follow these steps - you may need to repeat them several times:
- hold a hot water bottle or heat wrap around the pipe
- pour hot, not boiling, water over the frozen end of the pipe with a watering can, jug or kettle
When you think the pipe may be unfrozen, try switching on the boiler again. You may need to reset the boiler to do this. If the boiler fires it up, it's fixed. If not, you could try to unfreeze the pipes again.
Still got a problem? Book a callout.
An engineer can unfreeze the pipe and advise you on ways to prevent this in the future.
What could be the cause?
In long periods of cold weather, the condensate pipe of your boiler - a waste pipe that carries condensation from the boiler to your drain outside - can freeze, especially if it's exposed or incorrectly installed.
This can leave you without heat and hot water as the boiler has an in-built safety device to prevent any damage to the system.
- View More: British Gas My pipes have frozen
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=2759
My wall heater isn't working properly
It's not easy to tell exactly why a wall heater isn't working properly. But before you call an engineer, try these tips to see if you can fix it yourself:
- check the gas and electrical supplies to the wall heater are turned on. It's surprising how easily they can get accidentally switched off
- if you've got a permanent pilot light, check it hasn't gone out -this is a very common problem with older appliances. To relight, follow the instructions on the wall heater
- has the wall heater been lit properly? Check in the user manual if you're not sure
- check the control tap is turned on once the heater has been lit
- try turning the control tap to the highest setting for a short while
- are other gas appliances affected? If so the problem is bigger and you need to book a callout
Whenever you're checking the wall heater, always check with the user manual that you're doing it correctly. There are also usually some user instructions on the appliance control panel.
Still not working?
If you've done all the checks and still can't get the wall heater to work properly, book a callout.
- View More: British Gas My wall heater isn't working properly
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=4582
I can't get my central heating thermostat to work
First check you've set the clock/programmer correctly and make sure the right heating option is selected - choose on or constant.
If you have a digital thermostat, you can look up any unfamiliar symbols on the display in your user guide.
Your user guide or manufacturer website may have some additional troubleshooting information too.
Still not working?
If you've done all the checks and still can't get the thermostat to work properly, book a callout.
- View More: British Gas I can't get my central heating thermostat to work
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=4584
My radiator is leaking
To limit the damage from any leak, turn off the valve at each end of the radiator, find a container to hold the leak, then book a callout.
If need be, direct the leaking water into the container by tucking a plastic bag behind the radiator.
If your radiator has a thermostatic valve
The valve may open automatically if the weather is really cold and the room temperature drops a lot. This will mean that water continues to leak even though the valve has been turned off. If this is the case, we recommend you book a callout.
- View More: British Gas My radiator is leaking
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=2722
My radiator is making a noise
Different radiator noises have different causes and different solutions - often easy fixes that you can try yourself:
This is caused by a water flow rate through the radiator that's too high. Solve it by turning the radiator valve fully on by turning the taps anticlockwise.
A ticking radiator is completely normal - it's just the radiator warming up or cooling down. If the noise is coming from under the floor, it's probably due to pipes expanding and rubbing on the flooring or joists - again, usually nothing to worry about.
This can be caused by an incorrectly fitted thermostatic radiator valve. If you've recently had to move a radiator or had a new radiator installed, the problem may be that the valves may have been mistakenly swapped over.
To get this fixed, contact the installer.
Still concerned about the noise? Book a callout.
- View More: British Gas My radiator is making a noise
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=2741
The radiator's air release valve is leaking
There are a number of reasons why the air release valve might be leaking. Before calling an engineer for help, we recommend:
- Tightening the air release valve (clockwise - but do not force). If this fails to cure the leak turn off the radiator at both valves (wheelhead/thermostatic3 radiator valve and lockshield valve).
- Containing the water leak temporarily. A plastic bag tucked behind the radiator may help direct the water to a suitable container.
If you're not quite sure how to carry out any of these checks, it's always a good idea to have a look at the radiator manufacturer's guidelines for help. And if you try all of the above and the problem persists, we recommend booking an engineer.
3 In very cold weather, unless the thermostatic radiator valve has a dedicated 'off' position, the valve may automatically open if the room temperature drops significantly
- View More: British Gas The radiator's air release valve is leaking
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=2725
Do not try to fix any of the following problems yourself. Turn off the electrical supply to that part of the house at the fuse box and call us on0800 294 9650*.
Problems you should not try to fix:
- faulty pull cord and switches (once you've checked the bulb is working and secured properly)
- crackling or sparking lights
- can't get the bulb out of the fitting
- light switches or fittings that look damaged
Before calling us, check the lamps you've fitted are suitable (if you're using a dimmer switch, energy-efficient or fluorescent bulb).
Note that when it's very cold, larger fluorescent lights sometimes flicker when first switched on.
If your lights continue to flicker or a number of lights are affected, book a callout on 0800 294 9650*.
* Calls may be monitored and/or recorded for quality assurance and compliance purposes.
- View More: British Gas Lighting troubleshooting
- View Answer at https://www.britishgas.co.uk/HelpAndAdvice/LookUp/?SXI=17,CASE=1315