Potterton suprima were a very good boiler in their time, they were small and compact and would fit nicely inside a kitchen cupboard.
They came in many heat output sizes from 30,000 BTUs right up to 120000 BTUs and all in the same size case.
The 120s were recalled a few times due to problems and eventually withdrawn, but all in all, they were a good boiler.
The Potterton suprima had its faults though and one of them was the PCB or otherwise known as the printed circuit board.
Depending on how often the boiler was used the PCB problem would eventually show itself
The problem was because the boiler was so small the PCB which is located on the right-hand side if you are facing the boiler used to start to overheat when you looked at the PCB you could see burn marks.