In message , Tim Lamb
writes
Potterton Suprima 30-80

Boiler intermittently (every few days) locks out on what I assume is
overheat. Unfortunately the unit is some distance away at the flat of
an elderly (geriatric) relative so the symptoms leading up to the
lock-out are unknown.

Sounds like the classic PCB lockout problem, but without any useful
information, difficult to say any more

--
geoff