Removing a radiator

Hi

I'm trying to remove a double 700X600 radiator as the bracket is coming away from the wall. I turned the Giacomini globe TRV to closed
and shut off the lockshield valve on the other side. I then started to drain the radiator, after twelve litres or so I stopped as I thought this was more water than the radiator would hold (it should be less than a gallon or about 9 litres from what I understand). A futher clue that I had not isolated the radiator properly was that the pressure fell on my boiler.

What am I doing wrong? Do I need to use a shutoff cap on the TVR end?

Any help would be much appreciated.

Gaf

Hi

AFAIK most TRVs are supplied with plastic caps that replace the valve and 'screw' down the valve.

I would assume that without this they probably allow 'a small flow of' water to pass.

Some trv's dont shut off fully when closed, remove the head and put something in to push the pin fully down (5p peice usually does it) screw the head back on and water flow should now be stopped when valve turned off