PVJ3
page 12
12
5 Operation
5.1 System Operation
The system is designed to maintain a constant pressure in the discharge line
of a pumping system. The duty pump will start & ramp up & down in speed
maintaining the set point pressure until this duty pump reaches & maintains
100% speed for a short time delay. At this point the standby pump will start.
Both pumps will then ramp up & down maintaining the set point pressure until
the pumps reach & maintains (Standby stop speed) for a short time delay. At
this point the standby pump will be turned off & the duty pump will take over
by itself.
The duty pump will then ramp up & down to maintain the set point pressure
until this pump reaches & maintains the pump stop criteria plus a delay set in
(pump shutdown delay) & will then turn off stopping all pump operation until
the wake-up pressure is again reached.
The pressure will fall to the wake-up pressure set point where the duty pump
will then start the cycle once again.
Each time the system goes to sleep the duty pump will be alternated to the
next pump ready for the next operation.
If a motor fails the standby pump will be started & will remain as duty until the
faulted pump is put back on line.
Pump Stop Criteria
Duty Pump
– The duty pump requires 3 things to shut down-
1. The system pressure has reached & maintains set point pressure less
5kPa.
2. The motor speed is less & maintains less than the speed set in PUMP
STOP MINIMUM SPEED.
3. And the time value entered into LOW STOP TIMER parameter has timed
out.
Standby Pump
– The standby pump requires 3 things to shut down-
1. The system pressure has reached & maintains set point pressure less
5kPa.
2. The motor speed is less & maintains less than the speed set in PUMP
STOP MINIMUM SPEED.
3. And the time value entered into parameter STANDBY STOP TIMER.