hang on to your dreams.13

After about 5~10days ,or when the reading of the pressure gauge on the pump side of the filter has increased by about 0.2bars since the last backwash , backwash the filter as follows:
1. Stop the pump
2.Close the valves on the suction and return lines.
3.Open the cover of the pump and empty the filter gasket .
4.Refit the cover
5.Open the valve to the drain outlet
6.Turn the lever to BACKWASH
7. Open the valves to the suction and return lines.
8.Start the pump .Rinse the filter for about 1 to 2 minutes until the water in the sight glass is clear .
NOTE : Any electric heater must be off .
9. Stop the pump
10. Turn the lever to RINSE , start the pump and rinse for about 15~30 seconds. Stop the pump and turn the lever to FILTER . This is the normal operating position .
11. Close the drain outlet valve and start the pump . Switch on the electric heater if any .

----It is best to replace the silica sand of sand filters every 1-2 years for the following reasons:
a During backwashing, the filtration bed volume will expand upwards by 1.2 to 1.3 times. The water flow will drive the filtration layer to flow up and down, causing the filtration material particles to collide with each other. Backwash will let the small sand evacuate.
b.Some silica sands will be welded when the acid and alkali are changed due to insufficient purity;
Therefore, the longer the time, the worse the filtering effect of the sand tank. Since backwashing will consume and take away some sand, we need to replace the sand in the sand tank within the specified period.