In an earlier contribution to this discussion,
Mark Downey wrote:

my switchmaster 905 programmer has just packed in so i thought it was
about time to get a digital one ,Just come back from B&Q with a
drayton tempus 7. After taking the front off the switchmaster it
revealed this layout on the backplate

N-L-1-2-A-B-C-3-4

n-neutral
l-live
1 central heating ON
2 CH OFF
A.B,C- SPARE
3 HW ON
4 HW OFF

feeding this I had 2* 3 core cables
1st Cable - live neutral and the green cable screwed into the spare A
2nd cable - Brown into no1(CH ON) Blue into no 3(HW ON) and Green into
No4(HW OFF)

OK
the new Drayton has this layout on its backplate

N-L-1-2-3-4

N-neutral
L-live
1 HW OFF
2 CH OFF
3 HW ON
4 CH ON

so i connected the cables up as per diagram but did not know where to
put the green cable from cable 1 - and assumed it was an earth cable
so i plugged it into the earth socket . This configuration now leaves
me without a connection into no 2 (CH OFF).
I powered up the programmer and everything came on , Great I
thought.Set the time ,adjusted the timer settings and set to auto.
When the time came for the heating to come on - Nothing - No pump
running or 3 port valve switching over
Also nothing comes on in manual either.

So can any of you kind people help me.

Mark

Is your room stat turned up high enough to make the heating come on?

If you have a Y-plan system [See
http://content.honeywell.com/uk/homes/systems.htm ] you don't need CH-OFF
connected (but you *do* need HW-OFF).

Do you have a central junction box where all the wires are connected? If all
else fails, you'll need to trace the cables to find out what the other ends
of these 2 x 3-core cables connect to.

Incidentally, it's *extremely* bad practice to use the green or green/yellow
earth conductors for carrying live signals such as HW-OFF - *and* very
dangerous!
--
Cheers,
Set Square
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