Hi,
I opened the central, square-headedscrww on a central heating drain tap to drain the CH (surprise !) Flow was a bit reluctant at first and the movement of the screw a bit "rough". I sprayed a little WD40 around the screw and it moved a lot easier. After draining I tightened up the central screw but there is a slow but steady drip from the drain pipe. I have obtained a replacement washer and have seen on another drain tap that the whole of the central part itself unscrews. Now the part that unscrews from the body has a small "rim" that is milled. I have tried to unscrew this with a pair of "electricians" pliers but this just slipped (looking for some more meaty, bull-nosed pliers). Is there a "knack" for loosening this central part of the drain tap without 1) stripping the milled edge making it difficult to tighten when re-fixing, 2) applying so much torque that the soldered joint between the tap and the pipe gets torn apart. I don't want to risk damaging the drain pipe and have to replace the tap - the pipe on which the drain tap is fixed projects only a small way through the wall. It would be fiddly to replace a damaged drain tap on a damaged pipe
Thanks for any tips.
Clive