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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
7.8 Tank Sizing
For constant pressure systems, a pre-charged pressure tank should be used. The tank
should be at least 20% of the pump’s rated flow-rate in Gallons Per Minute (GPM). For
instance, a pump rated 10 GPM requires at least a 2 gallon tank.
7.9 Troubleshooting Constant Pressure Systems
A variety of conditions in a plumbing system can lead to less than optimum performance of
constant pressure control while using the factory default settings. The default settings are
designed to operate a range of plumbing systems, but there can be many variables in a
plumbing system that requires adjustment of the constant pressure parameters.
In order for the drive to enter sleep mode while operating in constant pressure mode, three
conditions must be met:
1. The pressure in the system must be at the pressure control point set by the parameter
psi SETPOINT.
2. The frequency declines to the shut off frequency (defined as MIN FREQUENCY plus
SHUTOFF FREQUENCY).
3. The time expired since the pump started after the last OFF cycle must be greater than
parameter T1ON or T2ON
When these conditions have been met, the drive will go to sleep. The duration of which the
drive is asleep depends on the rate at which the system bleeds down and the width of the
dead band. When setting and testing a constant pressure system, try to operate as close
as possible to the normal operating conditions. Low flow in a high capacity system (and
vice versa) usually requires some adjusting of the parameters.
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