The Duravit Happy D toilet has been available since the late 1990s. The toilet is part of a Happy D series of bathroom fixtures that includes sinks and bidets. Designed by Sieger, every Happy D toilet is supposed to resemble the letter D. Although the Happy D toilet is a little longer than many toilet models, it is a floor-standing toilet that can be installed in a similar manner to other toilets.
Turn the water off at the supply valve beneath the existing toilet tank.Flush the toilet to remove all water from the tank. While wearing rubber gloves, use sponges and paper towels to soak up any remaining water in the existing toilet bowl to get it dry.
Unscrew and remove the bolts located on the outside bottom front right and left sides of the toilet tank. Unscrew the valve from the toilet tank. Straddle the toilet seat and lift off the tank. Set the tank aside.
Remove the decorative caps covering the bolts holding the toilet base to the floor and unscrew the bolts (one on either side of the toilet base) with an adjustable wrench. Rock the toilet back and forth until it breaks free from the floor. Lift the toilet and remove it from the bathroom. Scrape away remaining excess wax from the floor and stuff a wad of paper towels into the hole to prevent sewage fumes from filling your bathroom.
Insert two new brass bolts into the base of the Happy D toilet, through the holes on either side of the base. Fit a new wax wring around the inside base of the toilet. Remove the paper towels from the hole in your floor. Lift the Happy D up and line it up on the floor over the hole. Rock the toilet back and forth over the hole until you feel the wax ring drop securely into it and the toilet is stable.
Lay a level across the toilet seat. Insert wood shims beneath the base of the toilet where needed to make the toilet base level. Screw new brass nuts onto the new brass bolts protruding from the holes on either side of the Happy D base and tighten them down with an adjustable wrench. Halfway through tightening, remove the shims and finish tightening the base down.
Attach the new tank onto the base and screw in the two bolts on either side of the tank base by hand. Attach the valve to the toilet tank. Assemble and install the internal tank flushing unit. Add caulk around the base of the toilet where it meets the floor. Allow the caulk to dry for a few hours before using the toilet. Turn on the water supply at the valve and test the toilet by flushing a few times with just water to make sure the tank fills and bowl empties appropriately when flushed.