Hi
I will assume you have taken the link out of the boiler where it says FROST STAT,,,,MAINS SUPPLY,,,ROOMSTAT,,,
the connection where is says ROOM STAT is the only bit that uses 240v and this is where you should have connected the wire from the room stat, link L and 1 in the lp711 and you should be good to go.
do not connect anything to the opentherm connection.