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E. FLUSHING PROCESS.
General – A Filter flush cycle is activated by the PLC which cause the flushing solenoid (SV)
and the motor (M) to switch on for preset time (TF).
When the solenoid is in ON position , hydraulic command is applied to the filter flushing
Valve causing it to open while the hydraulic piston starts it's movement across the screen.
After TF elapsed time the solenoid will returned to it's OFF position causing the filter
flushing valve to close while the filter internal pressure will restored the hydraulic piston to
it's starting position.
NOTE that the practical flushing time is the time required for the hydraulic piston to
complete it's movement due to a given line pressure.
In order to minimize the flushing time/waste of flushed water set TF respectively.
1. NON-DP FLUSH Is activated in three conditions :
1. Pressing the FLUSH switch.
2. Interval Timer TD (Internal) - If set by the operator.
Note that setting TD hrs/min is set to 0 , will disable this option.
3. Transition from OFF to ON.
(Applying short circuit for min. of 0.1 sec.at REMOTE inlets.)
2. DP FLUSH cycle.
A DP flush is caused by a differential pressure across the filter.
Signal at DP inlet for DP ON TIME (Factory set to 5 sec., can be adjust by the user) will
activates the DP FLUSH mechanism while a DP signal absence for more than DP OFF TIME
is consider as no DP signal.
Once a DP signal is registered , the flushing mechanism will execute a FLUSHING cycle by
activating the motor and SV solenoid for TF preset time.
After flush cycle completion the control unit will check the DP signal for TC preset time.
- If DP signal is removed after TC preset time the system will return to normal state.
- If the DP is still signaling after TC preset time , 2
- If after X consecutive flushes , (Preset by NFL , Factory set to 3 times ) , The DP signal is
not removed the system will enter a fault state - FLUSH FAULT state is declared (FAULT
Indicator lit constantly) and any further flushes are inhibited.
Note that entering 0 on one or both the above parameters will disable the DP FLUSH
--- Pressing the FAULT switch will reset the fault state and resume operation.
31
DPx on time
Actual DPx
signal
PLC DPx
signal
nd
ALARM.
DPx ON
flush cycle will be executed.
AF9800
DPx off time
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