Fitting a Radiator Valve with drain off ???????

[caslin]

My central heating system doesnt have a drain off so i doubt if its ever been drained down and treated for sludge etc. I want to fit a radiator valve with a drain off. How do i fit this to the existing radiator pipes once i remove the old valve?

Does it matter that the existing pipework has nearly 100 years of paint already on it will this effect the fitting of the new valve?

 

[ChrisR]

A valve with a drain cock on the back will fit in place of a normal one. Put paste or ptfe on the olive - old and new often don't fit that well.

To drain the system to do that, shut valves, drain a rad, remove it and attach hose to valve with garden hose - the tap connector is usually 3/4" = the same size.