When you have a problem with one or more radiators there are some actions you take before calling in your home maintenance plan assistance, or the emergency plumber if you have not taken out a plan in advance,
The actions you take depend upon whether there are several or just one radiator effected and the actions a householder can take are listed below.
Banging noises from the a radiator or several radiators
There could be several reasons why there is banging (possibly coming from the boiler).
- The boiler thermostat may be set high or be faulty creating a high hot water temperature. This can be tested by turning down the boiler thermostat (not the room thermostat).
- Lack of water pressure in the heating system. This can happen if the mains supply has stopped or the expansion tank has run dry with a cistern valve which has seized closed. Look at the pressure valve on the boiler if you have one, is this within the recommended settings for your boiler? If you try to investigate the problem and cure it yourself you should first switch off the heating and then test the components listed above
- Scale in the radiators. Build up of contaminants and scale can cause hot water to release any gases it is containing as the gases crystallise on any impurities, as bubbles form on the glass imperfections in a bottle of fizzy drink. To solve this read our article on radiator sludge.
Radiators are cool in one area of the home
If your central heating system is divided into heating zones one of these could have a problem which would then impact several radiators. The zones are often used to set a different temperatures in one area from those in another area.
If this is the case the first cause could be that the zone is set to off or that you have a timer on this area and it has not yet switched on that zone. Timers are electrical mechanical items and can be faulty or suffer from a lack of power / discharged battery.
An alternative cause is that the zone valve is faulty or locked into position. This is a more substantial task and will probably require a plumber to drain the system and replace the valve.
All radiators are cold
If you look at your boiler and it appears to be working this problem would suggest that the available hot water is not reaching the radiators.
The first culprit could be that the central heating pump is faulty. Alternatively the system thermostat or the room thermostat could be at fault. This will require a plumber or heating engineer to assist you.
You may be lucky that the cause is your central heating timer. Have the clocks moved forward or backwards and perhaps you have not adjusted the timer, or you did adjust it but by the wrong amount. Check that the timer has triggered the heating.
One radiator is cold
If you check and your other radiators are functioning correctly then this suggests that the problem is with this one radiator only.
You should check whether any of the radiator valves are switched off
- Is the radiator valve open or has it been closed. You can test this by moving the valve in an anti clockwise manner to open it
- Is the lockshield valve closed. Less likely but this is the valve on the other end of the radiator and it may have been closed if some work was done on the radiator. Again try to open it and see if the water flow commences.
- Is the thermostatic radiator valve (TRV) set at a low temperature. If the valve temperature has been set low then the valve will switch off the radiator at a normal room temperature. To set move the temperature to a high setting.
- Some of the valves are blocked. Scale in your system may have blocked the valves. Cleansing the system may clear this otherwise a plumber will need to clean or replace the valve.
Part of a radiator is cold
If the top is cold the radiator may need bleeding. See our article on radiator bleeding.
If the bottom is cold then the radiator may have a build up of scale in the bottom preventing water flow. See our article on radiator scale.
The center of the radiator is cold. This again could be caused by radiator scale and the radiator will need to be flushed with a power flush.
If your problem is that you have no hot water in your home there are a number of potential reasons for this as outlined in the following central heating video.