The pumping portion of the vertical pump is submerged in the pit, and the motor rests on a plate that also supports the rest of the pump shaft, discharge pipe, and volume. These pumps are not as prevalent as they once were due to their size and cost. These pumps tend to be very large, yet durable. Vertical pumps have been around the longest of the ejectors, about 100 years. If you have long stringy solids, many paper towels, or anything other than normal toilet waste, look to the manufacturer for a recommendation. In most applications, a standard non-clog impeller will be fine. The manufacturers are pretty clear about what types of debris their pumps can handle. Submersibles also are available in cutter, chopper, grinder, and non-clog hydraulic designs. The rail system is imperative for high use and troubled applications. These pumps sit on the bottom of the pit, but are available with a rail-type removal system. However, if the pump will run many times per day or frequently, a more-reliable double-sealed pump is a must. If the pump will run only a few times per day or if it will not run every day, a single-sealed pump will do just fine. How I select which type (one seal or two) is frequency of use. The cost difference between these two can be significant. Obviously, two seals are better than one. There are single-seal submersible pumps and double-mechanical-seal pumps. Submerging electric motors into water was taboo before then, but since the advent of submersible motors, submersible pumps have become quite common and safe. These pumps started to become common in the 1950s. If you have a sump pump in your house, most likely it is a submersible type. Photo courtesy of Liberty Pumps, Inc.Īlthough there are many types, variations, and different features of ejector pumps, it really comes down to three types: submersible, vertical, and self-priming. It features all-cast-iron construction and 2-inch solids-handling capabilities. This is a 1/2-hp submersible sewage pump, the Model LE51A.

When it comes to systems using submersible pumps, a large access opening is inherent for each pump 18 inches round per pump in most cases. The owner will at some point want to peek his/her head in the basin to see what’s going on. They will know the space requirements of their equipment and can assist you in determining load.įinally, when it comes to the basin cover, think access. Whatever the case, the manufacturers of the pumping systems are the best people to turn to for a recommendation on the basin size. If the only water entering the pit is clear and is merely storm drainage, you may in this case not have to worry about room for solids, but rather a massive inflow caused by a 100-year rain. Even in applications where normal toilet waste is the only thing being drained into the pit, the debris that can build up in the pit can be stifling to a level control system. Having enough room in the pit will make it less likely to hang up controls and allows room for the necessary maintenance from above. This can destroy control systems, power cords, and eventually the pump itself. It forms a crust on the top of the water that is unbreakable by inflow. Grease rises to the top of the pit and hardens. The size of the basin can be a huge disadvantage a larger basin than normal is only a slight advantage. Grease is a very challenging media for any ejector pump. The absolute worst application in a commercial building is a basin that receives waste from a grease trap. When should one fight for that space? When is it ok to shrink the size of the pit? Any application where solids will be introduced to the basin should raise a red flag.

This is where your knowledge of the application will cause you to fight for that space or make the decision to allow for a smaller pit. With that said, the demands of modern day building design may not allow for this. Most codes state that the minimum sump level is three feet below the lowest inlet in most cases, this is simply not enough. Here is a rule of thumb for proper usable basin space: Proper level control requires a minimum of four feet from the lowest inlet to the bottom of the basin, and you need at least a foot on the outside of each pump and a foot between them (if not more) depending on the type of media you will be pumping.

Belowground sewage ejector systems