Wow this thread has exploded since I posted . To get the siphon started you can either use a tradition method (i.e. suck or self-starter) or you screw whole thing into tap, put sucking end of hose in tank, make sure the bottom valve is open, and then turn the tap on. You don't need to have the tap going the whole time as it only sucks the water through - which you don't need when the siphon has started... Geddit??
well, here's some bad bad drawing that might explain it better...
HTH
p.s. Paint always seems to chop out words :evil:
It says : "tap on (but only at first)","valve open"
and
"tap on","valve shut"