MANUALPC-2010 CHAPTER IV - OPERATION Page 45
7.1.1 - Time Interval
This option allows the operator to set a cycle schedule with a
fixed interval of days between successive backwash
operations. Pressure differential is not considered. If this
option is selected, the program asks for the number of days
between backwash cycles and then returns to the Backwash
Submenu to specify the starting date and starting time of the
day.
The standard (default) value for the backwash cycle is 14 days
following the initial startup date set on the Backwash Submenu
screen. It can be changed at any time by the operator.
7.1.2 - Pressure Differential
This option causes a backwash cycle to be initiated when the
difference between the influent and effluent pressures at the
filter exceeds the set amount. The difference entered can
range from 1 to 99 psi or kg/cm
2
.
7.1.3 - Time or Pressure Differential
This option causes a backwash cycle to be initiated when
EITHER the specified interval number of days has passed OR
the specified difference between the influent and effluent
pressures exceeds the set amount.
The default difference value is 5 psi or kg/cm2. It can be
changed to any value in the range of 1 to 99 psi or kg/cm2.
The time interval between backwash cycles can range from 1
to 99 days.
7.1.4 - Time and Pressure Differential
This option causes a backwash cycle to be initiated when
BOTH the specified interval number of days has passed AND
the specified difference between the INFLUENT and
EFFLUENT pressures exceeds the set amount.
The default difference value is 5 psi or kg/cm2. It can be
changed to any value in the range of 1 to 99 psi or kg/cm2.
The time interval between backwash cycles can range from 1
to 99 days.
7.1.5 – Flow Rate
This option causes a backwash cycle to be initiated when the
main recirculating flow rate, measured by the square wave flow
sensor, falls below the set amount.
Submenu 7.1.1
Submenu 7.1.2
Submenu 7.1.3
Submenu 7.1.4
Submenu 7.1.5
Days between
Backwash Cycles:
Backwash starts when
Influent Pressure minus
Effluent Pressure
exceeds: 5 psi
Backwash starts when
either Time OR
Pressure Differential
is reached.
Time (days): 7
Backwash starts when
both Time AND
Pressure Differential
are reached.
Time (days): 7
Backwash starts when
flow rate falls below:
140
gpm