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Radiator Troubleshooting & Maintenance

How do I bleed a radiator?

Bleeding a radiator means getting rid of any air that has built up. Radiators should be checked at least once a year as any build up will affect the radiators performance. Bleed keys (vent keys) are readily available from a plumber’s merchants or DIY Shop. The necessity to bleed your radiators much more frequently than this is indicative of a problem with your system (which can often be rectified by cleaning out the system and refilling it in accordance with BS5449 section five commissioning).

To bleed a radiator:

  1. Ensure both valves at the bottom of the radiator are open.
  2. Attach the bleed key (vent key) onto the bleed valve (air vent) at the top of the radiator.
  3. Slowly unscrew the air vent and have a cloth ready to catch minor drips;
  4. When the sound changes from a hissing to a gurgling it means that the air has almost been vented. Be careful not to allow too much water to escape so keep a small cloth hany.
  5. Retighten the air vent.

What do I do if my radiator is leaking?

If you detest a leak, immediately close both valves to isolate the leaking radiator. Then open the air vent to release the pressure in the radiator which will stop, or at least slow down, the leak. Contact us immediately with details of the fault and the original purchase.

With all the necessary information to hand we will try and determine the cause of the leak (either a manufacturing fault or a problem caused on installation) and the best way to resolve the problem. We will do our best to find a solution in quickest most inconvenient possible.

Why do all my radiators get hot except one?

If all the radiators on the system get hot, bar one it is usually due to the water not flowing properly throughout. It is highly unlikely that the problem is caused by a blockage as a result of a manufacturing error. The following steps should help rectify the problem:

  • Making sure the radiator has been bled properly and that no air is trapped in the radiator. Depending on the position of the radiator on the system this might take more than one go.
  • Fully open to ensure water can flow into the radiator. Some radiators may have flow diverters to ensure the water flows in the right direction. If so, check that the radiator has been installed the correct way round with the diverter as close to the 'flow' as possible.
  • Check whether your radiators need 'balancing' and if so, balance it accordingly.

Please note: It is highly unlikely that the problem is caused by a blockage as a result of a manufacturing error.

My plumber needs to 'balance the system'. What does 'balancing' mean?

'Balancing' involves adjusting the flow of water through each radiator on the heating system so that all the radiators are running at equal temperatures and take an equal amount of time to reach their operating temperature. Your plumber should 'balance' the system after installing your radiators. Failure to balance a system correctly is often the cause of cold spots on radiators, radiators failing to heat up properly, or radiators making noises. These symptoms are rarely due to manufacturing faults.

What is an air vent / bleed valve?

All radiators will come with some form of air vent (also called a bleed valve). You will find it at the top of your radiator and it enables any air (see below) that has built up at the top of a radiator to be let out or 'bled' from the radiator. You will need a special air vent key or possible a small screw driver to do this.

The first time the system is filled it is air that is vented. Further periodic venting of the heating system is actually releasing hydrogen which is the by product of rusting in the system. If regular bleeding is required it’s a strong indication that the system requires draining and refilling incorporating a corrosion inhibitor.

Why is the radiator making a noise and what can be done to stop it?

Noise from heating systems is usually the result of poor installation and only very occasionally is caused by faulty products. Radiators are only vessels containing water and without moving parts so often any noise heard is being transferred from elsewhere in the system. The likely cause of any noise in your radiator could be one of the following:

  • Banging from pipework – There is likely to be insufficient space for pipe expansion (copper expands 1mm lengthways per metre), and therefore if pipes are trapped between floorboards and joists you may experience a "clanking" noise.
  • Banging from radiators – They may be too tightly wedged on their brackets.
  • Whooshing/whistling water – The pump may be set on too high a setting and/or the radiators are not balanced correctly.

How do I clean my radiator?

If you need to clean the surface of your radiators you should use warm water and a small amount of washing up liquid only. Anything abrasive, solvents and spray cleaners – such as those intended for cleaning sanitary ware, tiles and counter tops – should NOT be used as they can damage the finish of the radiators and valves. If you have a specific mark on a radiator that cannot be removed using standard methods, please call us for further advice.