While you wait for answers, we may have found some information which could help you.
Click here for Time Optima MainsTrianco Optima Boiler Programmer Fault (QA73)?
how do i depressurise a ferrolli optima boiler?
high pressure when heatings on?
Pilot light will not ignite?
Big bang on ignition?
Why does the Hawk II Optima keep turning on central heating without request?