How to Plumb a Grinder Pump

For homeowners, learning to plumb a grinder pump is an easy way to save money, as you won’t need to call a serviceman to fix the issue. If you need to replace this pump, do it as soon as possible to prevent overflow in the sewage system.

Tools and Materials

  • New grinder pump
  • Screwdriver
  • Socket wrench
  • PVC Seal
  • Wiring (if needed)
  • Connections (if needed)

Step 1 – Buy a New Grinder Pump

Buy the appropriate make and model of the replacement pump and make sure that it’s a grinder type. Don’t get confused with other types of pumps like sump pumps, which you also might have installed in your system. Grinder pumps are used in sewage systems for chewing up and converting the waste to slurry so that it can be easily pumped out to a conventional city sewage system. Verify the capacity, amperage, phase and HP ratings of the new pump. These need to match your control panel and power supply. To avoid injury or damage, read the supplied instruction manual thoroughly before installation.

Step 2 – Disconnect the Old Pump

Your grinder pump system is connected to a separate circuit breaker according to local code requirements. Before starting, disconnect all power supplies for your safety. Many pumps have an automatic thermal overload system, which may start an overheated pump unexpectedly. Carefully remove the cover with the ventilation pipe of your sewage basin. All liquid and debris should be removed. Once the basin is clean, disconnect the discharge piping from the pump’s discharge connection. Be very attentive when removing the pump’s wiring. Pull out the pump with the chain or cable attached to the lifting eye bolt (or on a rail guide or lift-out system, if provided).

Step 3 – Install the New Pump

If your pump doesn't come with a lift-out system, it’s advisable to install one for easy removal during maintenance or repair without disturbing the discharge piping. The lift-out system should be located opposite to the waste entry opening so don’t block this area. Rails should be properly anchored to the basin’s floor. Fit the pump to the lift-out system adapters. Lower the pump into the basin. Complete all wiring according to the instructional circuit diagram. Add additional wiring if required.

The pump must be connected to a properly grounded receptacle. Ensure that the switch float alarms are operating freely and won’t contact the piping. Connect the discharge piping to the pump’s connection. Use proper sealant if necessary. The discharge piping shouldn’t be smaller than the pump’s discharge diameter.

Step 4 – Test

Once the piping connections are made and checked, you can run and test the pump. Turn the power supply on. Test the pump by filling the waste basin until the pump turns on and make sure that the discharge check valve is fully open. Check the operation time until the alarm goes off. Audible and/or visual alarms should be visible. Check for leakage. Once it’s working, the system is ready for automatic operation again. Replace the basin cover and lock it if applicable. If you’re not sure, you can get always ask an electrician to check if you’ve wired everything properly.