How to fix common heating problems

While you need a qualified professional to install a heating system maintaining them is not difficult and most tasks take no time at all to complete.

How to fix rushing sounds in pipes

Possible cause: Air or gas bubbles in the system.

What’s the solution? Bleed the radiators (see How to bleed a radiator). If the problem continues, report this repair to us.

How to fix a radiator with a cold top

Possible cause: Air trapped inside.

What’s the solution? Open the bleed valve so that it can escape (see How to bleed a radiator). If the problem continues, report this repair to us.

How to fix a single cold radiator

Possible cause 1: The radiator’s manual control valve is turned off.

What’s the solution? Open/ turn on the valve.

Possible cause 2: The thermostatic radiator valve (TRV) could be incorrectly set.

What’s the solution? Reset it.

Possible cause 3: The TRV might be faulty.

What’s the solution? Report this repair to us.

How to fix your radiators when they’re all cold

Possible cause: Your boiler’s thermostat or timer is incorrectly set or faulty.

What’s the solution? Check and reset if necessary. If the problem continues, report this repair to us.

How to bleed a radiator

Keeping your radiators well-maintained will save energy as they’ll function more efficiently. If your radiator is cold at the top but hot at the bottom that means there's air in the system and you'll need to bleed your radiators.


Never bleed your radiators when they're hot otherwise scalding water could be released.

You will need:

  • A radiator bleed key or a flat-head screwdriver
  • A cloth

Step 1: Turn off your central heating and allow the radiators to cool. Work on the downstairs radiators first, starting at the first radiator on the circuit.

Step 2: All radiators are provided with a bleed valve in one top corner to allow trapped air to be released. It’s a square shaft inside a threaded plug (a round hole with a square inside it). Use a radiator bleed key (or in some cases a flat-head screwdriver) to turn the shaft anti-clockwise to open the valve. This should be between a quarter turn and a half-turn – don’t unscrew it by more than one complete turn.

Step 3: You’ll hear the trapped air hissing as it escapes. Hold a cloth beneath the valve to catch any water, and as soon as the first trickle appears close the valve by turning the bleed key clockwise.

Check all of your radiators as you may need to bleed more than one. Work on the downstairs radiators first and then move on to the ones upstairs and bleed them one at a time as required.

Turn your system back on and re-pressurise the boiler if required, the manufacturer’s manual should explain how to do this. Your radiators should now work more efficiently. If you find you have to bleed your radiators frequently, report this repair to us, as there is likely to be a fault somewhere that is allowing air to enter the system.

Watch this step-by-step video showing how to bleed a radiator, with expert advice and top tips to help you complete the job with confidence.

Changing your time and temperature Heat Events on your thermostat

If you are on the district heating system and your property was part of the ECO project, you can use your thermostat to change the time and temperature for your heating.

Your thermostat allows you to set up to six time and temperature periods a day to suit your lifestyle needs. These are known as ‘events. Your programmer will be pre-set with a factory default setting for efficiency.


If you are happy with this you do not need to adjust anything.

To change the default program:

Step 1: Press the PROG button until the first pre-set time and temperature event appears on the display.

Step 2: Use the + and - buttons to adjust the time of the first event.

Step 3: Press the UP or DOWN buttons to select the temperature you want.

Step 4: Press the PROG button to confirm this change and move to the next event of the day

Simply repeat this process for each event.

Watch this step-by-step video showing how to change the time and temperature of your heat events

Temporarily increase or decrease the temperature using your thermostat

If you are on the district heating system and your property was part of the ECO project, you can use your thermostat to temporarily increase or decrease the temperature.

Press either the UP or DOWN arrow to override the current program. This override will automatically be cancelled when the time of the next programmed event is reached

To turn your heating off altogether, for example if you are going on holiday, you can press the UP and DOWN arrow buttons at the same time and use the arrows to select a low temperature. This will override the thermostat and stop it from turning on your heating.

To return to normal, press the UP and DOWN arrows again.

Watch this step-by-step video showing how to override your heating.

Top-up your energy billing unit

If you are on the district heating system and your property was part of the ECO project, below are instruction on how to top up your payment meter

Your payment meter should update automatically however if it doesn't update within an hour of you purchasing credit or you need to top up instantly, you will find the pin number of your recent purchase on the bottom of your receipt. It should have 10 numbers

Normally your screen will show how much credit you have left. The ‘CR’ shows your credit and the ‘E’ how much you can use in an emergency

To begin adding credit:

Step 1: Press the ENTER button and select Add credit by PIN and press ENTER

Step 2: Using the UP, DOWN, PREVIOUS and NEXT buttons, enter the number of your PIN. When you have entered all 10 numbers, check they are correct and use the directional keys to select DONE and press the ENTER button. Your balance will update

In an emergency, you can use up to £5 of emergency credit. This allows you time to buy and top up. Once the emergency credit has run out, your heating will switch off and you will need to add more credit before you will be able to use your heating again

To use your emergency credit:

Step 1: Press ENTER and then press the DOWN button until use ‘is indicated. ’ emergency credit

Step 2: Press the ENTER button and your emergency credit will be active.

Watch this step-by-step video showing how to use your energy billing unit.

I have no heating and I’m on the communal heating system

If you live in a flat where we control the central heating system, we will often turn this on between the months of October – March.

The maximum it will be on 9 hours over a 24 hour period. Most of these hours will be overnight when it is coldest but there is a boost between 2pm to 4pm and again between 7pm to 9pm. These times are not the same every day as if it is warmer the system will naturally be on for less time.

If you would like to check whether the communal heating has been switched on, please contact your local housing office.

If you think your boiler has broken down and you have no heating or hot water, please call us.

For other repairs you’d like to report a repair to us, the easiest and quickest way is to do this online.

Copyright © B&Q plc.

B&Q has kindly given Southampton City Council permission to use these DIY tutorial videos to provide advice and guidance for council tenants. In using these videos, Southampton City Council is neither endorsing nor recommending B&Q products or methods. Other DIY self-help tutorials are available online. Simple repairs of this nature should only be undertaken if you are fit and healthy to do so and have the necessary tools and safety equipment. These repairs are undertaken at your risk and Southampton City Council accepts no responsibility for any damage or injury as a result of DIY repairs relating to these videos