under warranty I certainly would not remove the pump. Give them the entire unit. Dont give them a reason to point the blame your way. Before you do anything, make sure all faucets are off, all low point drains are shut, the hose to make the pump suck from the fresh tank is closed, the hose to siphon from the bottle is open, finally the water heater bypass is open and the cold entry-hot exit valves on the water heater is closed.
Make sure all connection at pump are tight, and start pumping now. If still nothing, then disconnect the "inlet" side of the pump, and attach siphon hose there.
still if nothing!! Does the pump suck correctly from the fresh tank? If the pump does nothing from the fresh tank, then the pump is definitely bad.
I started with nothing, and still have most of it left
2001 Jayco KIWI 23B
2003 Jeep Grand Cherokee 4.7 AWD