setting clock of economy 7 horstmann boiler?

ihave recently shifted to a flat with economy 7 boiler.its having a control box on which a clock with 24hr is present.outer to it summer and winter time written.there is a button written off and timed.a button for 1 hr boost along with a dial is made.a couple of days before i set the clock at 10am to summer time at 10am in the morning and boiler button kept on timed status.now its not heating water.when i turn dial the light does come at certain time .but i heard that there is preset time in it that it works in economy 7 hrs.but it does not heating at all.i do not get hot water any time of day.if i have put wrong clock time then atleast it should work any time of day.when i turn on boost button then only it heats water. what should i do? How can i set my boiler clock?if anybody can help me.thank u.