Sadly it's impossible to tell from the photo. We can see the wires labelled valve, stat, and pump coming in but not what they are connected to at their final destination. Unfortunately wiring colour rarely offers any help because the colours chosen are at the discretion of the original installer.
It will be a matter of tracing each wire to find out where it goes and then checking it matches the Y Plan diagram I posted earlier in the thread. One oddity For example is the cable you have labelled 'pump' (red, black, yellow) it doesn't seem to have any of the wires connected to an obvious neutral connection.......but obviously if the pump is working it must have somewhere
It will be a matter of tracing each wire to find out where it goes and then checking it matches the Y Plan diagram I posted earlier in the thread. One oddity For example is the cable you have labelled 'pump' (red, black, yellow) it doesn't seem to have any of the wires connected to an obvious neutral connection.......but obviously if the pump is working it must have somewhere
