On Fri, 25 Apr 2008 11:56:40 +0100, Chris S wrote:

(1) Is the rubber seal at the end of the hose supposed to be
sufficient to keep the joint water tight?

Short answer: Yes.

Long answer: Check that both side of the rubber washer are undamaged and
that the faces it mates against are smooth and that the washer is properly
seated into the hose end before you screw it on. Hand, bit more than just
fingers, tight should be fine.

A this a new, untested, hose there is a possibilty that the crimp between
the hose and fitting is leaking rather than the washer to valve. It might
be hard to tell if the leak appears at the back of the "nut" rather than
from the threads.

(2) Is it good practise to use PTFE sealing tape on these screw
joints? Or is the use of tape a sign of a poorly connection?

May hide the problem rather than curing it. The thread is there to force
the washer against the end of the valve. That is where the seal is not in
the threads.

--
Cheers
Dave.