CH Programmer

Hi All
I have just bought a new central heating programmer (Horstman Centaur - Plus C27) to replace the existing electro mechanical programmer (Glow Worm Master Mind) which has gone on the blink.
The instructions that come with the C27 show various wiring diagrams which are a bit confusing although I think I have identified the correct one (gravity hot water with pumped heating via roomstat and cylinderstat) which shows terminals N,L,3 and 4 being used on the new programmer. My difficulty is in how I identify the correct wires that currently connect to the existing programmer. Helpfully the C27 instructions have a series of terminal mappings various programmers being replaced by the C27 - unfortunately the Glow Worm Master mind does not feature.
Can any of you help me out here?
Rowdy
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You didn't make a diagram of the existing wiring before you took the old one off ?
The L & N connections speak for themselves. They're the live feed from your consumer unit (fuse box). The other connections you need should already be at the old programmer. One from the CH Motorised Valve and one from the HW Motorised Valve. All other connections should be in a junction box which is already wired.
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