How to Troubleshoot a Diaphragm Pump

A diaphragm pump is a displacement pump that removes liquids through a one-way system of valves. The flow of liquids is controlled by a flexible diaphragm barrier within the pump. This barrier expands when liquids enter the pump chamber.

A flooded field can be drained with a diaphragm pump.

As the pressure increases, the liquids are forced through the diaphragm into the exit valve. Flood waters, sludge and slurry can be safely drained away with a diaphragm pump. If your pump is not working correctly there are a few simple troubleshooting steps you can use to sort out the problem.

  1. Check the power running to the pump to determine if there is electricity in that location. Test the pump in a second supply to see if the problem is with the pump. Use a working electrical device with your current power supply to see if the outlet itself is functioning.

  2. Inspect the hose clamps securing the hoses onto the fittings of the pump. The fit of the clamps should be tight and securely gripping the hoses in place. Replace any hose clamps that are damaged or not performing properly.

  3. Follow the entire length of each hose and check for cracks or damages. Replace any broken hoses. Air will get into cracks and prevent the hose from allowing the pump to prime itself.

  4. Remove the hoses and clear any blockages inside that may be preventing airflow. Clean the pump fittings where the hoses attach so they are free of debris and build-up.

  5. Remove the screws holding the pump closed and open the pump. Check the O-ring in front of the pump valve to ensure that the ring is seated firmly in the valve. The O-ring is a black, circular gasket that creates an air-tight seal within the pump.

  6. Inspect the valve behind the O-ring and the ring itself for signs of wear or bloating. Replace both parts if they are not in good condition or if the parts don't form an air-tight seal.

  7. Tip

    Clean out your pump hoses after a large job to ensure no sediment or dirt gets lodged in the way.


    Do not attempt to troubleshoot your pump while it is running or connected to a drainage source. You could hurt yourself and damage the diaphragm.