Answer:
The Vormax flushing system is designed to clear your bowl using a primed flush. What this means is that as soon as you press the trip lever, the valves will open to start the bowl flush. If the trip lever is held down for too long this allows air to enter the flushing system. You will need to prime the bowl again to flush out any air that may have been let in. A correct flush would be to press the trip lever down all the way and immediately let it go, let the tank refill, and then flush again. Repeat this process 8-10 times.