I'm looking at a couple of frost-free sillcocks. Each one comes with a
wedge-shaped half-gasket that goes between the mounting plate and the
siding. The gaskets come attached to the sillcock with a rubber band.
In each case, the thicker part of the gasket is at the bottom of the
mounting plate. If mounted to vertical siding with the gasket in that
orientation, the sillcock will slope towards the inside. If mounted on
shingles or clapboards the sillcock will slope even more towards the
inside of the house. This seems like the opposite of what I would want
for the water to drain out when the valve is closed.
I had assumed that the gaskets were just shipped in the wrong position
and should be reversed for installation, but then I looked at a similar
unit installed previously by a plumber. It has no gasket, but it is
clearly pitched toward the inside of the house. The geometry of the
tubing is such (there is a double 90 right after the sillcock) that
the angle was unconstrained by the rest of the house piping, so this
was either deliberate or careless.
Am I missing something? Wouldn't it be better to pitch the sillcock
towards the outside so water can drain in normal operation? I suppose
pitching the sillcock (and the short piece of pipe to which it is connected)
towards the inside makes it possible to drain completely from the blead
port in the associated stop&waste valve, but that's the extraordinary
case rather than the common day-to-day one...