If your heating system is more than about five years old it could be worth checking to see if the system is likely to scale up or the water difficult to circulate due to a sludge build up. If you live in a hard water area, scaling of the boiler can take place; this reduces the efficiency of the boiler consequently using more fuel making it more expensive to run.
To check this, draw off about a pint of water from the system and check the colour, this should be a dirty grey colour if it is normal, if it is black then you will have sludge building up, a rusty or brown colour indicates that corrosion is taking place.
If you find that sludge or rust is evident you will need to add an inhibitor, available from all plumbing or heating supply outlets, always ensure that you de-scale the system first. To de-scale the system first empty the header tank completely or until the water stops running out of the outlet hose. If the system is a number of years old it is better to flush the system through by draining and refilling a few times until the water is clear.
Now add the de-scaler to the header tank and refill the system. Turn the boiler to a high setting and run for about a week. Check the instructions to see if the de-scaler requires neutralising before draining of the system and refilling.
Now add a good corrosion inhibitor to the tank and refill the heating system, start the pump which will distribute the inhibitor throughout the whole heating system. This should be done every five or so years to ensure that your heating system keeps in good working order.
Picture: Simon James