Finally changed my old mechanical siemans CH and DHW programmer to a sunvic 207 XLS digital display device. My problem is that I can fire up the DHW, but I'm unable to do likewise with the Central Heating. I have a Potterton Primera F using a mid positional valve and one room thermostat which is definately on. I have kept the original back plate for the new programmer. Could it be a new wiring set up or what? If wiring any idea the config. Thanks in anticipation.
Best wishes from,
Gibson.
Best wishes from,
Gibson.