Folks,

I'm hoping someone could help with a problem i have with a garden tap.
I've recently moved in to a house about 4 years old, the garden tap
looks like it was installed in a couple of minutes by the housing
developer straight through the kitchen wall to the garden. There is a T
piece from the cold water pipe under the sink, the main pipe goes along
the back of the cabinet a few inches then up the kitchen sink tap and
the other goes up a couple of inches and then straight out through the
wall to a tap. There is a stop tap up from the T piece to shut water
off to the garden.

With the stop tap fully open the garden tap as extremely low flow of
water, hardly enough to move a sprinkler connected with any length of
pipe. If i run the cold tap in the kitchen sink for a couple of seconds
the flow increase and the sprinkler is able to work, but only covers
4-5 feet either side.

The kitchen sink taps are fine as are every other tap in the house. I'm
wondering whether the stop tap or i guess there is a one way valve
somewhere in the piper before the tap to prevent contaminants from
coming back up the garden tap to the water supply. But before I take
anything apart I wondered if anyone could recommend a place to start?

Thanks in advance

Ben.