HIVE Dual Channel Conventional Boiler

Hi, I have just purchased and fitted a dual channel HIVE system and it is almost working 100%....but there was no wire behind my old analogue controller for water....just 3 wires...L N and the common for live transfer so in effect if I hit the hot water option it just comes on at the switch as I can't heat water separately and never could unless it was the immersion in the hot press. Does this system require additional wiring to the receiver to turn on the immersion? Otherwise am I right in saying that the water option only is redundant? Hope all that makes sense. Thanks in advance.