Issue: Pump Hums but Pushes Very Little Water
Possible Cause: Impeller may be seized by debris
Troubleshooting: Unplug and remove the pump from the pond and inspect the pump intake to ensure there is no debris restricting the impeller. Remove any debris, like rocks or sticks, which may have become lodged around and above impeller.
While the pump is still out of the pond, lay it on its side and plug in the pump to see if the impeller spins. If the impeller does not spin, use a screwdriver or similar tool to kick start the impeller.
Additional Note: Sometimes a brand new pump will not work and lock up due to being "water tested" at the factory and then sitting for a time until the new pump is sold. When this happens, try to manually turn the impeller to free it up.
Possible Cause: Pump may be air-locked.
Troubleshooting: Air has gotten into the impeller chamber. Tilt the pump while it’s in the pond to allow air to be released from the chamber or remove the pump from the pond and re-install, ensuring that the impeller chamber is flooded with water.
Issue: Pump Pushes Very Little Water
Possible Cause: Plumbing clogged with debris.
Troubleshooting: Disconnect the pump from the pipe. This will allow the plumbing to drain. Clogged debris may back-flush out of the plumbing and into the pond during this procedure. Inspect the plumbing to make sure no debris is lodged inside.
Issue: Pump Is Not Running
Possible Cause: Poor electrical connection, tripped breaker, blown fuse, or other interruption in power supply.
Troubleshooting: Check to make sure all electrical connections are working and that a qualified electrician installed and tested it. Note – Long extension cords may cause voltage drop at the pump and the amps to rise above maximum level. This can cause the pump to heat up and burn out the motor.
Additional Note: Try another breaker to eliminate the electrical problem.
Issue: Pump Operates Intermittently
Possible Cause: Not enough water in the pond.
Troubleshooting: Most pumps must be submersed in water to operate properly. Low water levels may cause the pump’s internal thermal shut-off to activate. The thermal shut-off will deactivate once the pump is cooled down. The proper water level must be established in the pond for the pump to work properly.
Additional Note: If this thermal switch is activated over and over it can cause the pump to be defective and stop working altogether.
Possible Cause: The pond is too small to support the volume of water needed for the stream.
Troubleshooting: The pond must be designed to provide enough water to the stream and waterfalls for proper circulation. When the pump is first started, it may be necessary to add a few inches of water to the pond in order to account for the water used to feed the stream and waterfalls. Upper pools and “check” dams in the streams are also very effective at holding water upstream when the pump(s) are not operating. Ponds that are too small may not be able to supply enough water to start the streams and waterfalls. This will cause the water in the pond to drop below the opening of the skimmer upon initial start-up and starve the pump of water.
Additional Note: Pumps that sit idle for a while (i.e. over the winter) and will not start up again when first plugged in again could have a calcium build up causing the pump not to start and lock up the impeller. Soaking the pump with 50% CLR and 50% water for 8 hours will usually free up the impeller.