Useful Technical Information


heating components

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Technical Information

If your boiler does not operate, please check the Manufacturer’s user instructions. We have detailed some helpful instructions, below (Please note, we do not accept responsibility for the misuse of these instructions). If in doubt, please call the Manufacturer’s helpline.


  • Check that the electrical supply to the boiler has not been interrupted.
  • Check pilot is alight on models with a permanent pilot.
  • Check that the pressure gauge
  • Is reading above 1/2 bar (5Mg)?


The water pressure gauge must read between 1 bar and 1.5 bar (10Mg-15Mg) when the system is cold. If the pressure is below the .5Bar (5 Mg), top up the pressure.

Filling Point

  • First, determine the type of filling device you have. There are a few Different types and in the majority of cases, they are not attached to the Boiler but on the pipes of your system (see diagram).
  • Identify the type of filling device you have, as well as, whether the device has two On/off valves or on/off off valve (see diagrams).
  • Turn off boiler on the electrical control switch.
  • Turn on the stop valve/valves and pressurise the boiler to the settings indicated above and immediately turn off the stop valve/valves.
  • If you have gone over 1.5 bar (15Mg) but are still under 2 bar (20Mg), this is acceptable. If you have gone over 2 bar (20Mg) keep an eye on the pressure and if it rises to 2.5 bar (25Mg) an engineer will be required to address the problem.
  • If you have to re-pressurise the system regularly (every day/week/month), ideally a system should only need pressuring once a year, you have a fault related to water leakage which may be on the boiler but most probably on the heating system. The obvious places are radiator valves on both sides of the radiator.
  • Touch the valves to check for dampness.

Cold Radiators

  • Check that your time clock/programmer is in heating mode (some programmers will need the hot water mode turned on as well).
  • Turn your room stat to its highest setting.
  • If your radiators do not come on then you have a fault

Inefficient Radiators

If your radiators are cold at the top and warm at the bottom, this could indicate air or hydrogen build up in the radiator. Releasing the air or hydrogen from the radiator air vent, should solve the problem, however, if you have a pressurised system, you will have to be more careful.

Releasing air or hydrogen from a radiator that is fitted on a sealed pressurised system, will cause the system pressurise to fall; the system must be depressurised using the guidelines in the paragraph titled “Filling Point”.

If the heating system has a hydrogen build up it is most probably due to corrosion in the system. (diagram of radiator with air build up).

If your radiators down stairs are cold at the bottom and hot at the top, this could indicate sludge build up in the radiator and your heating system will require a chemical clean with a power flush. (Diagram of radiator with sludge builds up).

Thermostatic Radiator Valves

These work by control the amount of heat the radiator emits by sensing the air temperature. So therefore setting the thermostatic valve to setting 3 will cause the radiator to cool once it has reached that setting. Remember that the valve is sensing the air temperature so do not expect the temperature of the radiator to remain constant it will fluctuate between on and off as required (diagram of Drayton try).

Clocks and Programmers

These units are very reliable, if you do not have any figures on the display, check that the power supply has not been interrupted i.e. accidentally turned off or a fuse has blown. It is important to note that, if a fuse has blown, then it normally indicates a fault occurring on a heating component. If you feel that you want to change the fuse, be aware, that it must be a maximum of 3 amps; fitting a fuse of higher amperage may cause serious damage to any electrical components on the heating system. (Diagram of Drayton programmer).

Creaking Noises

During heating operation you may experience creaking noises, especially, when the system, initially, starts in the morning. This is caused by the expansion of the heating pipes resting in wooden joists which are amplified at the radiators. These noises are usual and to be expected. There is not a lot that can be done to reduce these noises and you will soon get used to them.


Some boilers require ventilation for combustion purposes and this is provided by air ventilators fitted in the wall, floor or windows. The ventilator must have the following charesteristics:


Condencing boilers can, at particular times of their operation cycle, produce visible pluming from the flue turret outside. This pluming is entirely safe and non toxic which is made up mostly of water vapour. Please Click Here to see picture.

Gas Smell

If you smell gas: locate your emergency control valve and turn the gas off; open all windows and doors and extinguish any naked flames; and do not operate any electrical switches.

Call the National Gas Emergency Service?on 0800111999 for one of their engineers to attend, this is free service.

Water Leaks

If you have a water leak from a boiler or heating system, don’t worry, you will find that just taking some simple steps will contain the leak until you can contact an engineer;

  • Place a small plastic container under the leak such as an ice cream carton.
  • Place towelling or other rags around the carton.
  • Empty the carton as the water level reaches the top in to a bucket and place it back in position.
  • If the leak is on the boiler i.e. water dripping down from the boiler turn its electrical supply off.

Contact Us

Contact Us today or telephone on 0208 758 9799 to find out how we can help you. Just tell us your exact requirements and our helpful staff will be delighted to assist you.