A bit of a mess it seems

But: everything is safe!
Scaffolding has been certified, safetylabels have been placed after all the electrical drainvalves were disconnected (it must not be possible to operate them) and the boiler has been drained.
Reason: the main drain header has a sag and small cracks appear so it has to be repaired.
We take the opportunity to do this because the unit is stopped for a week to seek the reason why it's having a lot of vibrations.