Pump Fault Finding: 1

Pump Fault Finding: 1 is the first in a series of blogs that is written to help window cleaners using water fed pole systems.

The most popular pump used in pure water systems is the Shurflo 8000 series pump. These pumps are very reliable. However, at times there can be problems. This series of blogs will help you to fix or even avoid many common problems.

Remember, one frustrating aspect of fixing a pump problem, is that the reason why a pump is not working, may be a combination of problems. Additionally, what may appear to be a problem with a pump can actually be an issue with a controller, the wiring or the plumbing.

The Fault

Your Pump works but there is a high pitched scream from the pump. Or, you may have noticed that the pump has become generally noisier. You may also notice that the controller has started to display ‘DE’ when there is no dead end (DE) situation.

The noise that you can hear is probably caused by the lower motor bearing becoming corroded due to water getting into the motor through the bell end of the pump. You may also observe rust marks or white deposits around the pump body below the label.

Eventually the motor will seize and the pump will stop working. In this situation, the controller will likely display PS.

Checking the Pressure Switch

Tip: Take a few photos with your phone so that you can see where and how wires and hoses are connected. Additionally, always isolate the pump and controller before checking wiring.

So, at this point it is worth doing a few checks. Assuming the pump had become noisy and is now not working. And the controller is showing PS.

  • First check the wiring between the controller and the pump. Pay particular attention to the connections. If all is correct but the pump is not working, move to the next step.
  • Is it the pressure switch? Disconnect the two red wires that connect to the pressure switch. Carefully connect the two red wires together, using our Diagnostic Lead, or similar. This will bypass the pressure switch. If the pump now works, replace the pressure switch. If the pump does not work, move on to the next point.
  • Reconnect the red wires to the pressure switch. Disconnect the pump from the controller. Briefly connect the pump to a 12V battery. If the pump works, this indicates a wiring fault between the pump and the controller. Reconnect the pump and check the wiring. Alternatively, if after this simple test, the pump does not work, move to the next point.
  • You have completed the tests and the pump is not working. The pump may even buzz but not work when connected directly to the battery. This indicates that the pump has seized, most likely due to water ingress.

In cases like this, the pump is beyond economic repair and we recommend that it should be replaced.

To prevent this problem from happening again, fit a pump cap over the bell end of the pump.


This blog is a guide to troubleshooting pump problems on water fed system that operate at 12V. Any investigation work, wiring or plumbing should only be carried out by a competent person.