Potterton Puma 80 - Central Heating

[ds7775]

HI All,
I have a Potterton Puma 80 , the hot water seems ok ( all be it a little too hot ),but when i use the central heating the boiler fires for about 2 minutes then stops, if i turn the heating knob to full,then the boiler fires and all rads heats up.

it seems like the actual dial is only acting like a on/off switch !

the room thermostat is set at 24 degrees.


All rads have been bled, the pressue is about 1.5 !

any ideas are welcome

ps: no taps are dripping

thanks

 

[Agile]

The temperature sensors need checking.

The main problem sounds like a failing diverter valve!

Are you sure you have no dripping taps or leaks on hot water pipes?

Tony

 

[ds7775]

just tried again now i am back home, i turned the heating on , the burners came on for about 20 seconds then shut down, so i turned the CH temp to full and all the rads are now bouncing hot ! seems i have no temperature control ?


is a divertor valve or temp sensor something the average person can change ? if this is failing then how come it works when the boiler ch temp is on full?

oh........i have checked all taps and no drips where found !

see here: http://www.youtube.com/watch?v=brRzmaWkYVQ

at about 2 mins 20 this happens