It will last about 15 minutes, then the boiler will go back to normal operation. If the boiler does this for more than half an hour, please ring to arrange an appointment on 0330 123 9559. 'Save' function - this is only seen when an adjustment is made in the menus, and then saved. Does not appear in normal operation.Some things seems pretty straight forward and like they’re common knowledge, but I’ve run into this a few times with my students that feel embarrassed to ask what all the numbers on the lens mean. There is no reason to feel stupid or embarrassed if you don’t know this, it is sometimes confusing. So I’m going to run through them one by one.