Brian Reay wrote:

We have an long outside pipe run to the outside tape, at an estimate 4m.
It has quite a 'drop' on it, perhaps 1.5m over the 4m.

While the tap has a small drain screw, which I always use, and of course
I turn off the water in the winter (in fact whenever the tap isn't in
use), enough water always remains to cause a problem if we get low
temperatures- either a burst pipe or a failure in the solder joint.

I've removed the tap in the past to ensure the pipe is fully drained but
this is a 'faff' and I would prefer a quick method- ideally one my wife
can use (she is the main user of the tap). I've thought of either
another 'tap' with a wider 'bore' "tee'd" off the pipe to either drain
it or admit air at the top of the 'run' but has anyone another method-
this can't be a problem unique to us.

(We mainly use rain water collected in a 'butt' for watering BTW, the
tap is only used when the butt is empty or either clean water or a hose
is needed.)

If you leave the outside tap open in winter it is surprising it actually
produces enough pressure to burst. There's no dip in the pipe to retain
water? You could replace the whole run with plastic which is less
likely to burst, though it can force the connectors off.
--

Roger Hayter