problematic potterton combi 100/puma 100 ch fault

[miniestate]

Hi
I am trying to help a friend out with a problematic potterton boiler. The boiler switches on fine and has no problem supplying ample hot water but is lacking in the heating department. She can only get a maximum of around 3 radiators working at one time, i have read that these boilers suffer problems with the wax capsule in the diverter valve but would like another opinion before changing this.

Thanks

 

[ollski]

Sorry don't really have a different opinion its usually the capsule as long as the system isn't full of muck and the pump is running properly....not a job I'd envy anyone taking on either.

 

[weargas]

dripping hot taps can cause the problem too. They stop the wax capsule from getting the right heat readings to tell it to move.

 

[miniestate]

i'm pretty sure i can rule out the dripping tap problem as i isolated the mains after reading someones post on a similar boiler, i have recently removed the majority of old pipework (as it was al 15mm) and renewed so i dont think there is a blockage, and when the water was drained it wasn't very mucky.