my combi boiler is an optimax 25 ov dont quote me on that im almost 100% sure . . . . . its igniting for hot water but nothing happens at all when i try for heating. no i do not have a timer on and no my thermostat is never used so its not a problem with that. my water pressure is 100 % fine. i may be a girl but im not stupid so if your comment is going to be about any of these please dont bother. please help i am sooooo not paying a plumber thats gonna rip me off like the last 1 tried 
