i have had problems with my heating it was fine last year but now when i put it on it would not work, i called a plumber out who after looking around told me he thinks it needs cleaning to which he did he put some kind of stuff in the tank in the loft then came back after a 3 week wait he then took all the rad of and cleaned them out after setting all the rad back on and playing with them he said it would be ok now, well it never was and i still keep getting the problems he returned and after an hour or so of messing with them he said the pump seemed ok but was old and should not get as hot as it was and would change it for another amount of money but also it could be the therm coupling (i think) more money being on my own with very little spare x refusing to help i was hoping someone could direct me how to go, it is an old back boiler and he said it is gravity fed and way out of date yet till now has served me and the kids fine hot water is ok but very little heating