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Bleeding a radiator

(Your responsibility)

General advice

• If the top part of a radiator is cold, this is because air is trapped in the system. Bleeding the radiator releases this air and allows hot water to fill the system.
• Check what type of boiler you have. Do not bleed the radiators if it is a combination boiler. Please contact us. If you have any doubts, call us to check. Types of combination boilers are:
  • Worcester (all types)
  • Potterton Lynx
  • Potterton Puma
  • Gloworm Swift Flo
• Always turn off the heating system before bleeding a radiator, otherwise the pump will draw more air into the system.
• If the whole radiator is cold, make sure it is turned on by checking that the radiator valve is open. If it is turned on, it will need to be checked by a plumber.
• If more than one radiator is cold, the whole heating system will need to be checked by a plumber. Contact us.

You need

• Special radiator key (available from us)
• Rag or cloth
• Bucket

What to do

• Check what type of boiler you have to see whether it is safe to bleed the radiator. See General advice above.
• Turn off the heating system before you start work.
• The bleed valve is the small square nut at the top end of the radiator.
• Place the key over the valve and hold the cloth around it to catch any water.
• Gently turn the key anti-clockwise a couple of turns until you hear a hiss - this is the air being released.
• When the water starts to come through, turn the key back clockwise to shut the valve off.
• Take care not to unscrew the valve completely as the plug will come right out and hot water too.
• If the problem keeps happening, please call us.