wiring st9400c programmer

[Deano1978]

Ok i have quite an old y plan system and the programmer we had which was a clockwork type has given up. I know that the mid position valve is a honeywell v4073 which is compatible with the new programmer.

My question is this behind the original back plate for the programmer I have 2 wires for live & neutral, 2 for heating 1 live 1 neutral, 2 for water 1 live 1 neutral and 2 for the boiler 1 live & 1 Neutral.

What I want to know is the programmer shows NL1234

NL Neutral & Live from mains
1&3 Hot Water off & On
2&4 CH off & On

So where does the boiler leads go?

At present the old clock only has CH on & Off actually attached to the back plate and all the other wires connected to junction boxes.

Any help very much appreciated.

 

[doitall]

Depends on the boiler make and model.

 

[D_Hailsham]

behind the original back plate for the programmer I have 2 wires for live & neutral, 2 for heating 1 live 1 neutral, 2 for water 1 live 1 neutral and 2 for the boiler 1 live & 1 Neutral.

At present the old clock only has CH on & Off actually attached to the back plate and all the other wires connected to junction boxes.

Firstly, wire colours mean nothing, apart from the "2 wires for live and neutral".

What you have written in the first paragaraph is at odds with the second paragraph.

Can you clarify what you mean by providing a list showing which wire is connected to each terminal of the old timer?

You also mention junction boxes. Which wires enter and leave each box and what do they connect to?