How we can carry maintenance of heavy machinery in hotels? As we know that we cant disturb guest.And have to provide 24 hours services?

Hotels must have stand by for the important Machinery which will take care while doing the maintenance for the main machinery 

its depend on the machine,, some machines runs 12 hours or shift wise , which we can maintain in the time when it is off,, and some machines rub 24 hours ,, the 24 hour running m/c we should have the another stand by ,,, we will operate the stand by m/c and can do maintenance of the first one,,