help! replacing Honeywell ST7100 with Drayton Tempus 7

14 Feb 2010
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United Kingdom
Good afternoon,

My ST7100 was dead this morning so I went out to B&Q and picked up a Drayton Tempus 7 which seems to be a good match for my needs.

But I am confused about the wiring.

In the ST7100, there are ON, OFF, COM terminals for each of the CH and HW. Wires are connected to the ON and COM terminals, but nothing to the OFF.

In the Drayton Tempus 7 there is just ON and OFF for the CH and HW. Where does the COM go ? Simply just connect to the OFF ?

If this is more complicated than that and I need to dig into the Wiring Centre then this is probably not a job for me. Are there any temporary fixes to get the heating and hot water going ?

Many thanks.
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On closer look, there is a wire connecting the COM on the HW to the COM on the CH. The COM on the CH then also connects to the Live.

I thought these CH timer replacements were meant to be straightforward !!

Any help would be much appreciated.

I found this, which seems to be telling me how to map the Honeywell ST 7100 to the Drayton.... Compatibility Chary.pdf

but I think it is telling me to map

7 to H/W off
4 to C/H Off
8 to H/W on
5 to C/H on

Problem is there is no wire in 7 and 4. But I do have wires in the COM terminals and the H/W COM and C/H COM are connected and the C/H COM is connected to Live as described in the link above.

Where do those COM wires go ?

Any help would be appreciated
N to N
L - L
8 -HW on (3)
5 - CH on (4)

Forget about the common wires on the honeywell. They were there because the old timer had no internal linking. Your new one does.
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