I can't think which seals the guy is on about here cause that is a balanced flue boiler which doesn't rely on case seals for combustion product integrity.
So you'd be ok leaving the combustion case off then.
Nobut there are no seals on the combustion chamber front cover for that boiler if it is a balanced flued one.
Are you completely insane? Maybe the ones you have serviced have all been missing a case seal? Are you talking about the outer decorative casing? Couple of screws and 4 hook brackets?
Not completely no, not yet anyway but thanks for asking
Checked partsarena and there is a seal there so stand corrected.
You make me scratch my head, if it is balanced flue why is not a case seal important?