Hello folks! Yes its me again with the Potterton Suprima 80 which only
works on full temp setting. And then the water temp only reaches
60degree before the boiler goes off for 5mins. Comes for a few mins
when water out pipe from boiler reaches 45-50degree. Boiler is now 3
years, problem since new. Pump is set to fast speed, no problems with
pump, no air in system either. Previously had supurima 50 which worked
excellently with only half full temp setting, with all same pipe work.

What has happened so far...
1. New PCB
2. New Temp Sensor
3. New temp control pot
4. Another new temp sensor
1-4 made no difference, same problem.

Anyone with any advise welcome....