Low Water Flow – When the Pump Has Just Been Installed

• Look at the Speed Control dial located on the centre right of the controller’s circuit board
• Turn it all the way clockwise (up to 10) to maximum speed.
• This ensures you get full power output during testing.
• Running at low speed during setup can make it seem like there’s no pressure.

Surface pumps must be filled with water before they can pump effectively.

• Open the priming plug/bolt on the top of the pump head.
• Pour in clean water until full.
• Reseal the priming plug and start the pump.

If the pump isn’t primed, it will just spin and won’t move water, which looks like low or no flow.

Submersible pumps need to be well below the water’s surface to ensure a steady intake. If the pump isn’t deep enough in the bore or tank it may be sucking in air and causing cavitation which creates noisy operation, low flow and lack of pressure.

• Make sure the pump is completely underwater. This includes the inlet for the pump’s power cable.

• Check the pump inlet screen for mud or debris and clean it if needed.

1. Check for Airlocks in the Pipeline

Air trapped in your pipework can block flow entirely. This happens when air is stuck in the line (e.g. high point or bend) and the high flow rate of the water compress the air and prevents water from flowing past it.

Running your pump at a slower flow rate can slowly push the air out, but you can also:

• Tilt or lift the pipe slightly to let trapped air escape.
• You can also loosen a fitting at a point in the line where air might be trapped, allowing it to hiss out until water flows.

Once the air is purged, the water will flow normally.

Sometimes the issue is as simple as debris stuck in the intake.

• For submersible pumps: inspect the inlet screen for debris such as grass, dirt, or plastic wrapping.
• If installed in a bore, ensure the pump is not drawing in mud or grit from the bottom.
• For surface pumps: check that the suction hose isn’t blocked or sucking against a hard surface (e.g. a tank wall).

Always clean and flush the pump inlet during install.

If your solar panels are underperforming, the pump might not be getting enough energy.

Use a multimeter to check the voltage at the controller:

• Set you multimeter to detect DC voltage.
• Place the red (positive) probe on P+ and the black (negative) probe on P- terminals.
  • 24V pump systems should show 35V–55V open circuit voltage (Voc)

• 48V pump systems should show 65V–109V (Voc)
• 72V pump systems should show 80V–140V (Voc)
• If voltage is too low, clean the panels and recheck wiring.

Shading or dirty panels = poor flow.

Incorrect motor wiring can cause the pump to:

• Run backwards
• Spin weakly
• Not run at all

Check that the motor’s power cable wires are connected to the U, V, and W terminals according to the labels on the wires. Do not copy any previous installations or colour matching.

To test if your pump is running backwards, try swapping the wires from the V and W terminals. This will reverse the previous running direction.

If you are unsure, compare the labels on the individual wires and the labels of the pump controller’s terminals. You can also refer to installation guide in the user manual.

The pump controller may be getting an intermittent stop signal from a water level sensor or other sensor. While the pump is running, watch the lights on the front of the controller for any lights that come on other than Power, Pump and MPPT.

• If the Tank Full or Low Water lights come on, they may have a loose connection or not be installed properly.
• If the Fault or Low Power light come on, there may be an issue with your pump’s impeller or bearings.
• Check the troubleshooting guide in your user manual for details on how to fix these issues.

Conclusion:

Low water flow right after install is usually caused by:

• Airlocks.
• Poor priming.
• Low power caused by incorrect wiring or low light conditions.
• Sensor interference.

Follow each step methodically to isolate and fix the problem. Contact Commodore Australia’s Technical Support team for further assistance.