7
6.3
CONDITIONS FOR BACKWASHING
6.3.1
The requirements for backwashing are determined by the following conditions:
1. The flow rate through the filter bed decreases until it is insufficient to meet the
demand.
2. The debris removal efficiency of the filter bed decreases to the point where filtered
water quality deteriorates or results in dirt or debris returning to the pool.
3. The pressure gauge reading is 50kPa (7.2 psi) higher than the start up pressure.
Note: If the filter is connected to mains water, pressure rise is not an accurate
indicator as mains pressure tends to fluctuate. It is best to rely on the actual flow rate.
6.4
BACKWASHING INSTRUCTIONS
6.4.1
Switch off the pump and close the Inlet Valve.
6.4.2
Release the filter’s pressure by loosening the Pressure Release Valve until the pressure
gauge needle drops to zero.
6.4.3
Retighten Pressure Release Valve.
6.4.4
Depress and turn the handle 180° to the BACKWASH position. In the BACKWASH
position, water flow is automatically reversed through the filter so that it is directed
to the bottom of the filter vessel and up through the filter bed, flushing the previously
trapped dirt and debris out the waste line, see Fig. 3.
6.4.5
Switch on the pump and open the Inlet Valve. Backwash water will flow out through the
filter bed drain pipe.
6.4.6
When the backwash water in the sight glass appears clear, switch off the pump and
close the Inlet Valve.
6.4.7
Depress and turn the handle to the RINSE position. In the RINSE position, water flow is
directed through the filter bed as normal filter mode but out through the waste outlet.
This process settles the filter media bed into place and ensures any dirt or debris is
rinsed out of the filter, preventing possible return to the pool.
6.4.8
Switch on the pump and open the Inlet Valve. Rinse water will flow out through the
drain pipe.
6.4.9
When the rinse water in the sight glass appears clear, switch off the pump and close
the Inlet Valve.
6.4.10
Depress and turn the handle to the FILTER position and switch on the pump and open
the Inlet Valve for normal operation.