Every filter sand is different. When putting new sand into service, perform an initial backwash. Then set the pump to filter and note the current pressure. This is the starting pressure of your pump. You may find that this already shows up a bit in yellow. If the pressure gauge of the sand filter pump gets further into yellow, a backwash will need to be performed. Follow the steps below to perform the backwash:

Backwash with the 4-way valve

Step 1: Switch off the pump.
Step 2: Turn the 4-way valve to backwash.
Step 3: Unscrew the cap on the drain of the 4-way valve.
Step 4: Switch the pump on again.
Step 5: Switch the pump on again. (You can check this by feeling the water with your hand. As soon as no more sand comes with the water, you can stop.)
Step 6: Screw the cap back on the drain and set the 4-way valve back to filtering.

Backwash with the 6-way valve

Step 1: Switch off the pump.
Step 2: Turn the 6-way valve to backwash.
Step 3: Unscrew the cap on the drain of the 6-way valve.
Step 4: Switch the pump on again.
Step 5: Stop the pump when clean water emerges from the drain. (You can check this by feeling the water with your hand. As soon as no more sand comes with the water, you can stop.)
Step 6: Turn the 6-way valve to rinse.
Step 7: Turn the pump on for at least 1 minute, then turn it off again.
Step 8: Screw the cap back on the drain and set the 6-way valve back to filtering.