This is an instructional guide showing how to perform a back flush of the Portable Control Unit with a garden hose.

If your Portable Control Unit (PCU) is making a grinding noise while it is running (even with water in it), it is possible that some debris has entered the Impeller section causing the grinding sound. 

Note that it is normal for the PCU to make a "grinding" or "clunking" sound when the pump is activated and will go away once it becomes primed and flow is detected out of the discharge port in the tub.


Back flushing the PCU is a good practice to carry out every few months to aid in PCU performance and longevity. 

Simply remove the PCU from the tub connections (cap ports inside tub if you do not want to drain it), remove the filter and run water from a garden hose into the Heater Discharge Port. 

After flushing for approximately 30 seconds, turn the pump upside down to drain the remaining water. 

Check the Filter Bowl and Impeller at the bottom for any trapped debris, repeat if necessary. 

Reinstall the PCU to the tub and start up as normal. 

If grinding noise is still persistent then the impeller may need to be replaced.

If this does not work, and to ensure that we can provide you with the correct assistance, we require that you send through the following pieces of information to Customer Service:

  • Original purchaser information (shipping address, full name, telephone number, where product was purchased from)
  • Pictures of the spa setup (view of the entire spa, view of the inside of the spa, side view of the connector hoses to confirm level)
  • Picture of manufacturer's plate/serial number. PORTABLE SPAS: Serial number on the white label on the control unit which starts with "CSC" AND serial number on the outside of the tub liner which starts with "JL"