Common Problems With Central Heating
There are several central heating systems on the market, which include pumped systems, gravity systems and sealed systems. The most popular is the pumped system and the problems discussed here will refer to this system.The pumped system heats water through a boiler and circulates it round the pipework throughout the building by means of a pump. The most likely problem you may encounter will be cold areas in the system.
It is a good idea to get your system serviced once a year by an experienced heating engineer. There may be problems you don't know about and a good service will reveal such problems. You can contact a national service provider or a boiler manufacturer or even a local plumber, but the plumber should be Gas Safe registered and a member of a Competent person Scheme.
If a cold patch is at the top of the radiator, it could be fixed easily if you are careful. The system needs to be hot before you start working on it, but turned off before it is opened. The reason for this is to free air bubbles that may be trapped in the top part. This might not happen when the water is too cold.
The first step is to locate the air bleed valve and slacken it with a radiator key. Again, make sure the heater is switched off. Rags or a container could also be kept ready underneath to catch up any spills. If you have any welding gloves it is safest to put them on at this stage. Very carefully open the valve until a hissing sound is heard.
Let the steam or air escape until the first water comes out. The valve can now be closed and the heating can be switched back on. All the trapped air should be removed and the hot water should reach the top part now. If this problem regularly occurs, then a professional heating installer should be called in to find the cause of the problem.
If the cold part is at the bottom of the system then it's a sign of sludge or rust building up and settling at the bottom of the radiator. To fix this the radiator needs to be flushed with a hosepipe or any other powerflushing method. This is best done outside, so the radiator will have to be removed. A guide on removing and refitting a radiator should take you through all the steps.
When you find the upstairs part to be cold it most probably would be the cistern in the loft that ran dry. This should not happen, so rather call an appropriate engineer to sort it out. As to the cistern itself, it may be the ball valve that is faulty and that could easily be fixed by clearing obstructions or replacing worn parts where necessary.
In the case of the downstairs part being cold, it indicates a possible broken pump. If rust or sludge builds up, all radiators may become cold or not warm enough, but if one radiator is warmer than another one on the other side of the house, this could mean an imbalance where the nearest radiators may get all the hot water.
When there's no heat at all, check that the power supply is turned on and if so, check whether a fuse hasn't blown. Also make sure the pump is working and running. In the case of a gas boiler, check that the pilot light is lit and lastly check that all cisterns or feeders have not run dry. If all else fails, call the engineer.
There is also a proprietary heating system sludge remover available to be used with an open vent system. Before rust can build up, it gets broken down and removed through flushing. This sludge remover is to be added to the feeder tank and then, after a few days, the system can be emptied and refilled.
If you hear clanging noises when your system is in operation, there is a fault. Usually it's a result of lime scale or sludge building up and that is to be removed. Lime scale can be chemically treated and then flushed out, but it could also be an air lock, in which case the radiator has to be bleeded.
The temperature of the system should not be set too high or it could reduce the lifespan of the boiler. If you need to set it to high temperatures, it would usually be cheaper to consider better insulation for your home to make sure less heat escape.
When you see stains developing anywhere on the system it is a sign of a leak and should receive immediate attention. With a gas boiler installed to heat your system it is advisable to have a carbon monoxide monitor fitted. This might save lives in the long run.