Just a note of info. There are differences between a Vacuflush toilet ( Sealand systems) and other "vacuume toilet systems. Most notable and where a lot of maintenance
issues arrise, is the Sealand VACUFLUSH has a ball-valve at the bottom of the bowll that when acuated causes the vacuum to suck the contents out. The other manufactures utilize the SEAT as a seal to form the vacuum. Big difference in power
of vacuum force and maintenance
. The lid must be down to make the seal for flushing
. That is a big "gasket" to make is often the subject of lvacuum leaks
. Whereas the Vacuflush uses the smaller ball valve at the bottom of the toiet bowl to "seal" the vacuum. So, unlike the other systems, you can keep the lid up on a vacuflush toilet to watch you waste get sucked down and out. The others you have to keep the lid down during the cycle and hope all the wasted was taken.