I am in the process of adding a ball valve to my brew kettle and am designing a diptube to transfer wort to my primary. I've always brewed in 5-gallon batches so picking up the kettle and dumping it has never been a problem, but I would like to automate this process as much as possible and am wondering if I can just rely on gravity to drain the kettle as long as the kettle is higher than the primary vessel or whether I will need a pump to automate the entire process. I understand that this pump is not self-priming so I would to siphon enough to fill the pump to get it started, but that it would be able to drain the kettle much quicker once started. Speed is not that big of an issue at this point, but being able to drain all of the wort is a priority.
So, can I rely on gravity to drain the kettle after the ball valve is opened or must I use gravity and a pump?