On Jul 10, 8:10 am, "DJB" wrote:
I've fitted a new immersion cylinder but am having a problem with the
drain-off valve. When I bought the valve I thought it should have a fibre
washer, but a friendly plumber told me that it doesn't and I should instead
use 13 turns of PTFE tape. The problem is that even though I've tried this
a few times I can't get the damn thing to point downwards - and it leaks!
(the irony - having to use the drain-off valve for the first time because IT
leaks... grrrrr.) To me it doesn't seem right: the face of the valve seems
smaller than the face of the outlet on the cylinder as if something else
should be there. Searching the archives has left me thinking that this is a
1/2" BSP parallel thread and that what the plumber told me is probably
correct, but it still seems odd (to my naïve plumbing skills) that the
immersion element came with a nice washer but the valve didn't. I'm going
to try again this morning with even more tape, but thanks if anyone can put
me out of my misery and tell me if I'm doing anything wrong. I've put a
picture up hehttp://myweb.tiscali.co.uk/dbecker/drain-off-valve.jpg
David

You need LOTS of tape, and you can't unscrew it at all to get the
position right - you have to stop exactly where you want it. There are
alternatives to PTFE that are easier for where the final position is
important - my current favourite is screwfix code 42142. More
expensive, but you don't use much, it works every time, and you can
back the fitting off if you need to without breaking the seal.

A