Bowl should hold water.
How a VacuFlush is supposed to work: it's an electric toilet that uses pressurized flush water, so the breaker must be on, and so must the fresh water pump. Accumulated suction created by the vacuum pump sucks everything out of the bowl when you step on the pedal...the pump comes on and restores suction for the next flush...when the accumulated vacuum reaches the correct amount, the automatically shuts off until the toilet is flushed again. There is no wet or dry mode...You can add water by lifting the pedal before using the toilet...but after flushing there might be an inch of water in the bowl at most---with no reason to add any more until/unless it's needed for the next use. If the dome is seating correctly, that inch of water should stay there till the next flush...in fact, until it evaporates. If it doesn't, there's an air leak in the opening in the bottom of the bowl...which I'd bet real money is due to "operator error:" you're easing the pedal back up instead of letting it go to snap back into the place. It's spring loaded for a reason--allow the dome to snap back with enough force to seat properly. The same air leak is prob'ly also causing the pump to cycle...'cuz once all the water drains out of the bowl, the accumulated suction begins to pull air into the system that reduces the accumulated vacuum, which turns on the pump to restore it. First, try cleaning the gasket on the underside of the opening in bowl. Then start using the toilet according to the directions that were supplied with it (that same owners manual also includes the answer to your question, btw--in fact, includes the probable causes and cures for just about every symptom a VacuFlush can develop). If that doesn't solve the problem, you prob'ly need to replace the "ball shaft and cartride"...call SeaLand at 800-321-9886. If you don't have a manual for it, ask 'em for one while you're on the phone.
