Posted by Chuck(G) on April 19, 2002 at 12:05:17:
In Reply to: Leadpipes posted by Charley UK on April 18, 2002 at 12:27:31:
The selfsame thing came up a couple of years ago on either this list or TE. I believe the conclusion that was reached was that the 2nd valve entry leadpipe was designed to provide a more-or-less constant level of resistance, regardless of whether the valves were depressed or not.
Sorry to be so fuzzy on the details, but your post faintly rang a bell for me.