You can do anything you want to do to the HOLDING tank
...it's not actually a part of the VacuFlush TOILET system...SeaLand just packages holding tanks
with it and in doing so confuses the bejabbers out of owners who aren't familiar with the system.
Here's how it works: The VacuFlush toilet is a three component system--the bowl assembly, the vacuum accumulator tank (not to be confused with a holding tank) and a vacuum pump. The vacuum tank and vacuum pump may be a combined gizmo called the "vacuum generator," that includes both and works the same way as separate vacuum tank and pump. And thatís ALL there is to the VacuFlush toilet. The holding tank is NOT part of the VacuFlush toilet system...nor is the overboard discharge pump to dump the tank, nor is any vent line filter. Dometic Sanitation (formerly SeaLand Technology) does offer ďpackagesĒ that add all or some of those things to the toilet system, but itís important to understand, especially when it comes to troubleshooting it, only the aforementioned three components are part of the toilet.
The vacuum pump has TWO functions: it suctions the air out of the plumbing between the toilet bowl and itself while simultaneously pushing the flush the rest of the way to the tank, treatment device or thru-hull. The vacuum tank has a switch and a sensor on it that starts the vacuum pump when there's a loss of "vacuum" (toilet is flushed or an air leak in the system) and turns it off when the correct amount of negative pressure has been reached. How long it runs after the pedal has been released depends on the distance from the pump to the bowl...the shorter the distance, the shorter pump run time. The accumulated "vacuum" only pulls the bowl contents TO the pump..the pump has to push it the rest of the way. So if itís greater distance from the pump to the tank than from the bowl to the pump, leave the pedal down to keep the pump running a little longer and to rinse out the pump.
You need an owners manual for it. Call SeaLand --which is now owned by a company named DOMETIC, which is how they answer the phone
now and ask for one: 800-321-9886
To add the line going to the deck
pumpout fitting (which you may have install) is a simple matter: install a y-valve in the discharge line and run a new 1.5" line off it to the deck
fitting. That's all there is to it.
You're welcome to contact me directly if you need more help in understanding how to use and maintain a VacuFlush to keep it trouble free.