16
when the filter returns to a clean DP as evidenced by comparing the inlet and discharge
gauge pressures.
To alter the backwash duration, adjust the DIP switches on the ‘WASH’ timer as illustrated
in Exhibit 2. The lowest setting is 2 seconds and is selected by moving the first DIP switch
down. Duration time is increased in 1 second increments and is adjusted by moving each
DIP switch in sequence until the desired number of seconds is achieved. Refer to Exhibit 2
for an illustration of all possible settings.
2.4 Backwash Interval Timer
The Phoenix filter is designed to be operated with the DP switch provided. This ensures
that backwashing follows the contaminant load on the filter, which will often be variable.
The Phoenix filter has an additional advanced facility, which takes over from the DP switch
at times of low contaminant loading. This feature is called the backwash interval timer and
is factory set at 8 hours. This ensures that the filter does not spend excessive amounts of
time inactive during conditions of low contaminant loading. This facility avoids the problems
frequently encountered with mechanical equipment, which remains static for long periods of
time.
To alter the interval time adjust the DIP switches on the ‘TIME’ timer as indicated in Exhibit
2.
It is imperative that only one DIP switch is switched ‘ON’
. Note, this adjustment is
different from the procedure for setting the backwash duration timer.
Note:
Adjustments to both timers must be done when in filtration mode and not during a
backwash. Therefore, it is advisable to initiate a manual backwash immediately after any
alterations are made to ensure that the new settings have been registered in the control
system.
2.5 Fault Conditions
There are three fault conditions available on the Electro-Pneumatic model, including:
Valve Not Home:
Upon initiation of a backwash, an internal timer begins. This timer allows the Indexing Valve
to complete its 360-degree rotation within 60 seconds. If the valve does not return to its
home position within 60 seconds, as indicated by the position of the opto disc, an alarm is
signaled.
The fault lamp will illuminate both
RED
and
YELLOW
in color and the pneumatically
operated backwash valve will close. Please refer to Section 5.0 for corrective action.