A macerating toilet system allows for a toilet to be installed below and/or at some distance away from a home's main waste pipe, or soil stack. A macerating toilet shreds and liquifies the waste so it can be easily carried out to the waste line via a relatively small pipe. While macerating toilets have special installation requirements that differ from ordinary toilets, they are not impossible to install for most homeowners.
Determine the Placement of the Macerator
The macerator is a tank that sits behind the toilet itself. Your toilet feeds directly into the macerator, which processes the waste and wastewater and evacuates and it through a discharge pipe with the aid of an electric pump. The macerator can also serve other bathroom fixtures, such as a sink or shower, but can serve only one toilet. In many cases, the tank and its plumbing are all visible in the bathroom, but they don't have to be. The tank can be installed in the wall behind the toilet. This requires a longer extension piece to connect the toilet. It also requires that you install a removable wall panel behind the toilet, so you can reach the tank for repairs if needed.
Keep Your Bends Gradual
Most macerating toilets are installed in places where a standard toilet cannot. This means that the waste may have to travel a ways down the pipe lines to reach the main house drain. To ensure you get the longest runs possible, any time you have to turn a corner or change direction with the pipe, make a soft bend. It's preferable to use "long turn" fittings for all bends. If this is not feasible, it's better to use two 45-degree elbows than a single 90-degree elbow to make a 90-degree turn.
Go Vertical First
If your waste pipe needs to travel up at any point in its run, the vertical portion should be as close as possible to the macerator. There are limits to how long a discharge pipe can be, and because every foot of vertical height is equal to 10 feet of horizontal run, you will quickly run out of allowable distance if you don't lay your pipes strategically. The discharge piping can have only one vertical section; you cannot run vertically, then horizontally, then vertically again. Horizontal runs use gravity to move the waste and should be installed with a standard 1/4 inch per foot downward slope toward the main drain.
Your macerating toilet runs on electricity, so there needs to be an outlet near enough to the toilet that its cord can reach it without pulling and without an extension cord. This outlet must be located more than 40-inches away from the shower, as well. Because this is a bathroom, you will need to make sure the outlet is a Ground Fault Circuit Interrupter (GFCI) outlet. It cannot be switch-controlled.