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Pre-charge Mode Setup:
1. Navigate through the keypad menu to:
CHANGE PARAMETER VALUES > CONSTANT PRESSURE PARAMETERS
> PRECHARGE FREQ
Enter the Pre-charge frequency
2. Navigate through the keypad menu to:
CHANGE PARAMETER VALUES > CONSTANT PRESSURE PARAMETERS >
PRECHARGE TIME.
Enter the Pre-charge time in minutes
3. Navigate through the keypad menu to:
CHANGE PARAMETER VALUES > CONSTANT PRESSURE PARAMETERS >
PRECHRG psi.
Enter the pre-charge pressure in psi.
This value must be lower than the psi SETPOINT
4. Set the keypad to AUTO mode to operate the system
7.5 Lead/Lag Pump Control
When any analog CP system configuration is selected, the LEAD/LAG menu is available. See Table 18,
Lead/Lag Parameters, for lead/lag control options. Up to two additional pumps can be controlled
through programmable relays on the main control printed circuit board. When the parameter NUMBER
LAG PUMPS is greater than 0, both relays will convert to control of lead/lag constant pressure.
CAUTION: Activation of lead/lag control overrides the function of all programmable relays. Any
function of these relays, set up through the Interface Parameters, will be disabled.
Lead/lag control in pumping systems is a common practice to maintain pressure with highly variable
flow. The system is typically configured with a main pump controlled by a VFD operating in CP mode,
and with auxiliary pumps that are controlled by the drive. The auxiliary pumps typically operate across-
the-line at 60 Hz. They may be equipped with a soft starter to mitigate inrush currents.
If the main pump cannot maintain system pressure it will call for an auxiliary pump by closing a relay on
the control terminals. SD & 2XD Series drives can control up to two auxiliary pumps. There are
features to reduce oscillations and ensure smooth staging and de-staging pumps.
Lead/Lag Set-up
System Configuration must be set to one of the constant pressure modes when using lead/lag control.
See Section 6.5 for details. Lead/lag control is enabled when the number of lag pumps is set to a value
greater than zero in the parameter NUMBER LAG PUMPS.
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