I needed this information. I had suspected that only one of the control cables was needed (opentherm or relay switching). What difference does it make if both are connected?Needs the L&N to power the hub (already in place) and for OP's benefit either the 1&3 terminals (relay switching) or 2-core to the Opentherm module - no need for both AFAIK. Make sure the Opentherm cable is not connected to 230V on either end, or you'll let the magic smoke out.
The 2-core Opentherm cable needs to be connected as shown on Page 32 in this Install/Service manual:
Note the Link Wire on the 230V side of the boiler, which might have been removed if it was setup for a timer.
I have seen a YouTube video of this where the relay switching wasn’t used. Someone asked why that was the case but unfortunately an answer was not given.
Sorry for butting in but this is the only thread that I have found that answers my Wiser Kit 1 to Ideal Logic wiring issue.