potty potterton

[spaglemon]

hi all , this is my first post , i have a potterton puma 100 which i have just replaced the pump on , i put in some system cleaner and sludge remover , i have removed all radiators individually and flushed them through , and after putting everything back together i still have the same symptoms which are that the hot water works fine but if i put on the heating side the boiler fires up for about 20-30 seconds and then shuts down , however if i leave it set to constant it fires up every so often for 20-30 seconds then goes off again 3-4 hours later it comes on and works fine with all radiators piping hot , if anyone has any ideas i'd really appreciate a reply

just an update i've just had the diverter valve out and it was very cruddy inside have cleaned it up and re-installed it but there is no change , could it be a thermostat ?

thanks

craig

 

[Deleted member 2053]

First thing to do would be to switch on the central heating when the system is cold and test the tempterature of the CH flow pipe from the boiler. At least that will give you some idea as the whether the problem is with the boiler or the remainder of the system.