Thanks for your prompt and helpful advice. My only concern before swapping the C17 for a C27 is that the latter is listed on the Screwfix website as a 5-wire installation yet I only have 4 wires! Can you shed any light on this please?
Advice wanted please. I have bought a new Horstmann Centaur C17 to replace an old Landis & Gyr RWB252 programmer but find the installation wiring diagrams unclear for a DIYer.
The boiler is a Boulter Camray 5 pumped system. The old programmer connections are pictured here:
Can anyone...