I am replacing all my radiators and valves and thought it would be
useful to fit drain-off tails. I'm confident about fitting normal rad
tails with PTFE/compound, but the drain-off type need to end up in a
position where you can get at the drain key head and fit a hose -
ideally with the hose fitting pointing down. Sometimes this means
backing off the fitting from the fully tight position.

What is the recommended way of doing this? Even when you add more wraps
of PTFE it doesn't take much effort to turn it past the ideal position.
How can you judge when the seal will be pressure tight?

thanks

John

"john51" wrote in message
ups.com...
I am replacing all my radiators and valves and thought it would be
useful to fit drain-off tails. I'm confident about fitting normal rad
tails with PTFE/compound, but the drain-off type need to end up in a
position where you can get at the drain key head and fit a hose -
ideally with the hose fitting pointing down. Sometimes this means
backing off the fitting from the fully tight position.

What is the recommended way of doing this? Even when you add more wraps
of PTFE it doesn't take much effort to turn it past the ideal position.
How can you judge when the seal will be pressure tight?

thanks

John

=================================
I think you're a bit confused about how these valves made. They're normally
in two parts. One part (with large loose ring nut) is screwed into the
radiator using whatever sealant you choose (usually PTFE tape). When this
part is secure the other part - the main body of the valve - is attached by
fitting its tapered end into the part fitted into the radiator. This part
can be fitted in any orientation you want because it's secured by tightening
the ring nut - not by screwing in.

Have a look here for the general idea:
http://www.screwfix.com/app/sfd/cat/...60760&id=12381

Cic.

=================================
I think you're a bit confused about how these valves made. They're normally
in two parts. One part (with large loose ring nut) is screwed into the
radiator using whatever sealant you choose (usually PTFE tape). When this
part is secure the other part - the main body of the valve - is attached by
fitting its tapered end into the part fitted into the radiator. This part
can be fitted in any orientation you want because it's secured by tightening
the ring nut - not by screwing in.

Have a look here for the general idea:
http://www.screwfix.com/app/sfd/cat/...60760&id=12381

Cic.

Thanks Cic. I appreciate what you are saying, but I wasn't referring to
the type of drain-off valve you referenced, but the drain-off tail that
lets you drain a rad for removal after closing off the TRV/lockshield
valves. In this case - see for example
http://www.danfoss-randall.co.uk/default.asp?strSearchResult=tem8.asp?intPage=1332| intLang=2|strLang=en|intLevel=1|intLevel2ID=1332
- the drain-off part is on the radiator tail itself and screws directly
into the rad on a tapered thread like an ordinary tail.

John