Smart Solutions

Bigger Is Not Always Better

Tips from Wayne Water Systems on Choosing the Right Sewage Pump for the Job

Contractors who spend their days visiting customers for new sewage pump installations know that they often prefer larger, higher horsepower pumps. The common misconception that bigger pumps equal better performance leads to various issues and callbacks related to pumps’ short cycling. Short cycling generally occurs when the pump starts and stops frequently, leading to premature burnout. Use the tips below to educate yourself on properly sizing your sewage pump, which will prevent constant callbacks and, more importantly, dissatisfied customers.

  1. Before starting the sewage pump installation or replacement, consider the system capacity. System capacity, normally determined by the requirements of the dwelling (number of bathrooms, kitchen appliances, etc.), is extremely important when deciding the horsepower of the pump.
  2. Determine the total dynamic head for the system. Total dynamic head can be defined as the total height that the fluid will be pumped and is the sum of the static head and friction head. Static head is the total change in elevation from the fluid level in the pit to the highest point of discharge in the system. Friction head is an additional loss created as water flows through pipes, check valves, elbows, and fittings. Friction is a function of the velocity of the fluid and changes with pipe size, flow rate, and surface roughness.
  3. Consider the type of solids that the pump may encounter. No two sewage pumps are the same. One may handle solids up to 1″while another may handle solids up to 2″. Improper installations, such as effluent pumps instead of solids-passing sewage pumps, can lead to pump failure and flooding.
  4. Select the correct basin. After you have properly determined the type (horsepower, construction, switch, etc.) of sewage pump, determine if your basin will discharge from the top or the side. The average basin depth is 24″ for standard sewage pumps.
  5. Consider the type of impeller being used in the application as well. The vortex impeller is recessed inside the pump chamber, and the spinning action creates a swirl that pumps water through the system. The advantage of the design is that the impeller is not in the flow path, which greatly reduces the opportunity for clogging. The centrifugal sewage pump, in comparison, is more effective in moving water. However, the possibility of a clog is increased because all of the water pumped must pass between the impeller vanes.
  6. Consider your customers’ pumping needs. Will you be installing a simplex system or a duplex system? A simplex system is a single sewage pump in a standard basin and is the standard system for a level basement of average size in a single-family home. A duplex system includes two sewage pumps in the same basin. Consider a duplex system if the customer has an above-average sized basement or encounters daily instances of high water usage. Duplex systems often require the installation of a pump controller to allow the homeowner to properly manage each sewage pump individually.
  7. Test the new sewage installation to ensure maximum velocity is reached. Often times, improper pipe sizing, among other factors, can lead to sewage pumps failing to achieve the advertised gallons per minute. Properly calculating the total fixture units (dishwasher, bathrooms, washing machines, etc.) to find the correct pump capacity will ensure that you’ve chosen the correct sewage pump for the job.
  8. Select your pump system based on the required flow rate and total dynamic head to meet system demands. Most pump manufacturers publish performance curves indicating the flow and head capabilities of their products.

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