I am getting a Er4 code on my topside control occasionally. The circuit board and heating element have been replaced recently. Any Idea what the problem is? and if I can fix it myself?

Thanks

Newport Spa(Temecula)
United Spas pack, digital topside(brett Aqualine BL-46 board)
2 pumps, one 2 speed, no blower, ozone
240V

ER4 indicates that your flow switch is either jumped or is activated when the pump is turned off, so if your pump is running while this message is displayed the the system believes it should not be and you may have to replace the PCB, if your pump is not running then there is a problem with your flow/pressure switch and it may need to be adjusted or replaced altogether.