ahhh, what a dumb-arse...
805... N L 1 2 3 4
where
1 = CH on
2 = not connected
3 = HW on
4 = not connected
tempus 7... N L 1 2 3 4
where
1 = HW off
2 = CH off
3 = HW on
4 = CH on
need to wire
CH on - old 1 => new 4
HW on - old 3 => new 3
CH off - not...
A mop fell against my switchmaster 805 and broke the dial, I bought a digital programmer (tempus 7) to replace it after reading these forums (my system is from 1984).
The old dial based 805 let me turn the CH, "on", "off" or "timer" (same time as HW obviously) - but the there was nothing...