Phil L formulated the question :
They'll tell you to turn the pressure down by partially closing the stoptap,
which is what you should have done before buying a regulator.

Partially closing the stop tap, will not affect the pressure, except
when there is flow. The static pressure will remain the same as before.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk