On 2008-06-01 11:05:46 +0100, John Stumbles said:

On Sat, 31 May 2008 16:01:59 +0100, geoff wrote:

drop the pressure, funnel and tube into the top of a radiator


Doesn't work for rads with small vent plugs welded straight into the rad
(rather than 1/2"BSP plugs) or where the 1/2" tapping goes into an
immediate 90 degree elbow into the rad itself - tend to get liquid running
out of the hole and spilling back down the rad. IME anyway.

For these, the effective solution is to drain this particular radiator
(only) and to use one of the cartridge gel products.

I have found that trying to use these as suggested by the manufacturers
- i.e. against the system pressure - results in water ****ing out where
the nozzle is screwed into the radiator. Having empty space into
which to inject and no pressure works well. Then remove the nozzle,
refit vent plug part way and refill radiator.