65 | P a g e
Two conditions must be met to stage a pump:
1. The system psi has decreased to a pressure equal to psi SETPOINT minus STAGE PSI LAG.
For example, if the psi SETPOINT is 50 psi and you want to stage a pump in at 45 psi,
STAGE PSI LAG should be set to a 5.
2. The time set by STAGE PUMP DELAY has expired. This delay allows momentary drop in
system pressure without calling for a pump to stage in.
Pumps are staged in the following sequence:
1. The relay will close to start the stage pump.
2. The speed of the main pump will decrease to a value equal to MAX FREQUENCY minus
STAGE FREQUENCY REDUCTION. For example if MAX FREQUENCY is 60 Hz and
STAGE FREQUENCY REDUCTION is 5 Hz, the pump speed will be reduced to 55 Hz.
3. The main pump will operate at reduced speed for a period of time set by STAGE TIME.
4. When STAGE TIME has expired the system will resume normal constant pressure control.
Pumps are de-staged when the drive has slowed the main pump to maintain control pressure and the
auxiliary pump(s) causes a rise in pressure.
Three conditions must be met to de-stage a pump:
1. The system psi has increased to the value set by DESTAGE PSI LAG above psi SETPOINT.
For example, if psi SETPOINT is 50 and DESTAGE PSI LAG is 5 the pump will de-stage at 55
psi.
2. The time set by DESTAGE PUMP DELAY has expired. This delay prevents de-staging the
auxiliary pump due to momentary pressure overshoot.
3. The drive frequency to the main pump is between MIN FREQUENCY and the value of
DESTAGE MIN FREQUENCY plus MIN FREQUENCY. For example, if MIN FREQUENCY is
30 Hz and DESTAGE MIN FREQUENCY is 5 Hz, the pump will de-stage at 35 Hz.
Pumps are de-staged in the following sequence:
1. The relay will open to de-stage the pump.
2. The speed of the main pump will increase to a value equal to MIN FREQUENCY plus
DESTAGE FREQ BOOST. For example, if MIN FREQUENCY is 30 Hz and DESTAGE FREQ
BOOST is 5 Hz, the pump speed will be increased to 35 Hz.
3. The main pump will operate at increased speed for a period of time set by DESTAGE TIME.
4. When DESTAGE TIME has expired the system will resume normal constant pressure control.
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