Q: We have a Blessed Sacrament chapel with 24-hour adoration. What do we do during the Triduum?
A: The USCCB web site says pretty strongly, “Under no circumstances may perpetual exposition take place during the Easter Triduum.” http://www.usccb.
My suggestion – and that’s all this is – is that the lunette from the monstrance be brought to the altar after communion has been distributed at the Holy Thursday Mass of the Lord’s Supper. Let the priest remove the host and break it into four pieces in full view of the faithful. Place those pieces among the hosts that will be processed and kept overnight in the other ciboria.
Then before the Easter Vigil begins – or before the last mass on Easter Sunday begins – set out a new 3” host for the priest to consecrate. After communion, have him place it in the lunette, and have someone carry it reverently to the Blessed Sacrament Chapel, where it could be placed in the monstrance and put on view to begin adoration again at the conclusion of the mass.