How do I backwash my sand filter?
When the filter pressure rise 8-10 PSI over the clean starting pressure it is time to backwash. Turn the pump off and rotate the multiport valve to backwash. Turn on the pump and the dirty water will flow out the waste line. Once the water runs clear in the valve’s sight glass, turn off the pump. Rotate the valve to rinse. Turn on the pump for 20-30 seconds. This will clean out the plumbing lines and reset the sand bed. Turn off the pump, rotate the valve to filter position and begin to filter. Take a reading of this new clean starting pressure, so you have a reference point for the next backwash cycle. Water may need to be added to the pool to replace the backwashed water.
IMPORTANT: Make sure you turn the pump off each time you turn the multiport valve. That valve cannot be turned with pump running.