I fitted new Drayton TRV4 radiator valves to all my rads about 4 years
ago, and already two of them have started leaking where the valve pin
projects from the valve body.
Is this a common problem? Are they fixable or is the only solution to
renew the whole thing? Anyone have a magic solution for doing this
that avoids draining the system (it's an open vented system with a
header tank)?