So when you check expansion vessel and identify it needs topping up, do you drain the vessel completely and re-charge with air?every 4 years a full strip and clean / replace burner gasket etc also the normal yearly (normally allow half a day)
every other eg 1,2 and 3 etc (yearly)
check expansion vessel,
tightness test gas system,
clean maggy and top up with fresh inhby,
bleed rads,
check system pressure and top up,
check system controls are working,
clean condense trap and refill,
clean condense pump if there is one and check operation
gas rate system,
fga boiler
(normally allow 1.5-2 hours)