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