Place a rack inside a roasting pan and fill it with water until it reaches the bottom of the rack. Then place a roasting rack inside the pan.
Turn the gas on your Weber Q so it's open enough to light. Family Q users leave the large gas control knob off and turn the small gas control knob to the low position and ignite the Weber Q.
Medium and Baby Q owners turn the gas control knob to the low position and ignite.
Place a clean convection tray and trivet onto the grill, followed by the roasting pan with rack onto the trivet and close the lid. Allow approximatally 20 minutes for the Weber to reach the correct temperature.
Once the temperature of the Weber Q has reached 110°C (230°F) place the roast beef onto the roasting rack and place a meat probe into the top center of the beef pushing it down halfway, and close the lid.
Monitor temperatures of both the Weber Q and roast beef making sure it stays between 107°C (225°F) and 120°C (250°F) at all times. Make any necessary adjustments to maintain this temperature at all times.
Once the internal temperature has reached 60°C (140°F) internally for medium or 63°C (145°F) medium-well done, the roast beef can be removed from the Weber Q.