new house in nov, rads taking an hour to heat up, turned up the thermostat which was on 1 to 4,better for a couple of weeks then a loud banging coming from the boiler,had to turn it off called a plumber in,found a couple of new empty pump boxes in loft obviously had problems before. Plumber put a new pump in as he thought it wasnt turning round properly but didnt help,no heating. Came back a week later and flushed the system out noise gone but rads taking ages to heat up still especially when the heating is on too and the boiler is firing up all the time and then going off something not right, any ideas please?