With a brand new Blichmann 15 gallon Boilermaker - the vale/dip tube were already connected, No assembly other than the Thermometer.
I attached a 3 foot (1/2") silicone hose to the dip tube, with the bottom of the hose 2 feet below the dip tube. (to create suction)
I filled the pot with 7 gallons of water and opened up the valve.
It drained until around the 2 gallon level (already passed the dip tube level) when it stopped. The suction was never broken.
When I tipped the kettle to the side, then the remaining water came out, except for a few ounces.
So I can get my beer out, but why doesn't it drain on its own, down to 0.23 gallons?
It's a new pot, I don't think the O ring needs to be replaced. I can wiggle the dip tube a bit, but it was never removed.