heatline 24 boiler?

have moved into a new place boiler has knob missing to turn dial to radiator, although can use tweezers, never had central heating/boiler before and terrified , do i need to change anything else from summer mode??It is a heatline24 boiler, we already get hot water on demand, two seperate dials showing radiator on one and tap to the other, but both seem in a nuetral position, confused if turn those as well

dizzy lady
October 2008