So you think you need to bleed a radiator?

The first step to find out if this is the case, is to put the Central Heating on, leave it running for about 10 or 20 minutes and see if there is heat distributed evenly throughout the radiator.

If the radiator needs bleeding the bottom will be hot but not the top,  this is because air rises to the top but allows the heated water to flow through the bottom.

If only the top is hot after a significant amount of time, there is likely to be a build up of sludge in the central heating system and a Powerflush is needed.

Step 2, if you have confirmed that you need to bleed a radiator,  next you need to  check and top up the system pressure using the filling loop, either on the boiler or connected to the pipes somewhere near it.

If you do not know how to do this it may be worth getting in a professional for a boiler service, if one is due and inform them that you have a radiator that needs bleeding which can be done at the same time.  If you get topping up a boiler wrong, it can result in damage to parts in the central heating system and or boiler.

boiler pressure gaugefilling water pressure on worcester boiler


Bleed vent on radiator in Maidstone

Step 3 is to identify the end which needs bleeding, this usually has a tiny square metal point in that a radiator key will fit onto.

Make sure the heating is off, then place in the key and turn anti-clockwise whilst holding some tissue around the vent, only turn the key by a small amount until you hear air hiss out.

When the hissing stops and water starts to come out turn the key clockwise lightly until the water stops. Warning DO NOT OVER-TIGHTEN.

If no water comes or air comes out then you will need a central heating system repair

Step 4 is just to check the system pressure and top up if necessary.  1-1.5 bar on the pressure gauge is perfect.

Now test your heating system and see if the radiator heats up properly.

If not give KMC gas a call on 07980299733