The W-B Greenstar 29HE installation manual shows a "Y-S wiring module"
with a connection called "DV" or "Boiler/pump demand" but doesn't
explain what this does. Am I right in thinking that it's an input to
enable the boiler to fire only when the pump is running?

The FAQ mentions outside weather compensation but I can't find any
details on the web, can anyone enlighten me about this?

Can anyone suggest a cheap basic 3 channel programmer?

--
Dave S
(The return email address is a dummy)