While you wait for answers, we may have found some information which could help you.
Success
Message
Trianco Optima Boiler Programmer Fault (QA73)?
Why do my TRV's rattle?
how can i fix my ferolli optima 701?
high pressure when heatings on?
Pilot light will not ignite?
Big bang on ignition?
Optima failing to fire up?
OPTIMA 701 Ferrori heating problem?
optima 701 pressure rises when heatings on drops when off?
how do i depressurise a ferrolli optima boiler?
how can i fix boiler?
Why does the Hawk II Optima keep turning on central heating without request?