We have had a Potterton Suprima 80 for 8 years. It ran fine for 5, but
the last 3 years have turned into a nightmare which gets worse. We
have had 3 PCBs, the last one fitted 10 days ago, and the boiler is
still locking out. The thermistor and associated sensor have been
changed 3 times as well.

Does anyone know what more we can do to get this thing running as I
believe it should; i,e, without locking out?

Any advice welcome.

TIA
John