I have a Potterton Suprima 30 and guess what it locks out! The house
is 5 years old so guess the boiler is, surley the last owner did not
choose the model!!

Playing around and logging the times it resets, it seems to happen
more often when the hot water is hot in the storage tank. Also the
water does seem to get very hot!? The other day it would simply not
come back on until I emptied the hot water out of the tank!

Talking to my dad (ex plumber) and brother (ex Potterton Suprima
owner) We feel it could be the following in this order….

1. Faulty overheat sensor
2. Faulty thermostat allowing the water to get too hot and triggering
the above. (This is taken from another post so unsure if they mean the
one on the tank?)
3. Faulty PCB - taken on basis most people seem to have this.

If you could be kind enought to log your view and which part you would
change first. I see Cet Ltd can change the board for a good price but
guessing I could get a sensor cheaper and maybe worth trying first?
(Where would you advised getting these from?)

Many thanks for taking the time to read and reply with any comments, I
will post any more findings I have, and hopfully a resalution of the
problem befroe too long, its dam cold in the mornings!!