Any ideas welcome on this one?
I have a 6 year old Potterton Suprima 50 that has had the PCB (revision 11b !!) replaced nearly 18 months ago due to lock-out problem. Last few months have been having problems with it just not getting hot enough.
Both hot water and rads get lukewarm even though both cylinder and room stats are turned right-up.
The boiler fires up and runs for a minute or two every now and then. Control on bolier is flashing green which the pcb manual suggests that it has reached the required temperatue, but if a turndown either of the stats then I hear then click-off, so they are definitely asking for more from the boiler.
I thought it was the 3-ways valve initially as actuator was on last legs, but replacing it has made no difference. Cylinder stat is new too.
??