Can someone help me understand how to operate vulcan 90 central heating, it comes on in mornings at different

times, in the kitchen it has a lever to select temperature 0,10,20,30, when you slide it to 0 , I believe it to be off, but in the mornings I hear it on sometimes, is this maybe has dropped below zero and it automatically comes on, there is something that looks like a timer near the unit, it has 2 red and 2 green pins which could be start and stop times, but it doesn't make sense to me, also there is a switch auto or manual can someone explain this to me thanks