Wall hung toilets are different in that the plumbing doesn't come from the floor of the bathroom, but from the wall. Wall hung toilets are not actually hung on the wall. Instead, they are secured to four bolts which stick out a little over 2 inches from the surface of the finished wall. Wall hung toilets come in two parts: the bowl and the tank. Removing and installing a wall hung toilet is not much different than a floor mounted toilet.
Turn the valve underneath the toilet to turn off the toilet water supply. Use a wrench to loosen the valve nut. This is the nut securing the flexible water supply pipe to the valve.
Pull the flexible pipe off the valve pipe. Use a wrench to loosen the coupling nut at the top of the flexible pipe. This nut is securing the flexible pipe to the wall mounted toilet's water inlet stem. Remove the flexible pipe and washer from the stem.
Remove the nuts and washers from underneath the lip of the toilet bowl. These nuts hold the tank onto the bowl. Lift the tank off of the bowl. Remove the four nuts holding the bowl to the support bolts. Slide the old bowl off of the support bolts.
Line up the holes on the back of the toilet bowl with the support bolts and slide the bowl onto them. Put the washers on the support bolts and hand tighten the nuts. Use a wrench to tighten the nuts 1/4 of a turn.
Push the large sponge washer into the hole on the back of the toilet bowl. Place the mounting bolts on the bottom of the tank through the holes on the back of the bowl. Place the front of the tank flat against the sanitary bar on the toilet bowl.
Slide a washer onto each mounting bolt and secure with nuts. Place a supplied washer over the water inlet on the bottom of the toilet tank. Put a new flexible pipe onto the inlet and tighten the coupling nut to hold the pipe in place.
Attach the opposite end of the flexible pipe to the supply valve and tighten the valve nut. Turn the water supply valve back. Flush the wall mounted toilet and check for any leaks.
Place a silicone caulk tube into a caulking gun with the flat end of the tube against the back of the gun. Cut off the tip of the caulk tube with a utility knife. Squeeze the trigger on the caulk gun to apply a bead of silicone caulk around where the bowl meets the finished wall. Smooth the caulk with your finger.