Grundfos CU331SP, Installation And Operating Instructions Manual

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English (US)
11.7 Menu INSTALLATION
11.7.1 Sensor 1 (3.1)
Setting of sensor 1 connected to terminal 54. This is the feedback
sensor.
Select among the following values:
• Sensor output signal:
0-20 mA
4-20 mA.
• Unit of measurement of sensor:
psi
• Sensor measuring range:
0-120 psi
11.7.2 Motor speed high limit (3.2)
This parameter allows the user to limit the maximum speed that
the motor can operate.
Setting range is 1800 rpm to 3450 rpm.
11.7.3 Dry pump function (3.3)
This display shows the setting for how the Dry-Run indication
should be handled by the drive. This parameter can be set to
these values:
• OFF
• Warning
• Alarm
The default setting is “Alarm” which will stop the motor to protect
the pump. When “Warning” is selected the drive will provide a
Dry-Run warning on the display screen only and the pump will
continue to run. When “OFF” is selected the Dry-Run function is
disabled. Neither a warning nor alarm will be issued.
11.7.4 Power correction factor (3.4)
Power Correction Factor is used to adjust the sensitivity of the
Dry-Run function. Contact Grundfos for assistance if it is
necessary to adjust this parameter.
11.7.5 Protocol (3.5)
This display shows the protocol selection for the RS-485 port of
the CU331SP. The protocol can be set to these values:
• GENIbus
• FC
• FC MC.
If GENIbus is selected, the communication is set according to the
Grundfos GENIbus standard. FC and FC MC is for service
purpose only.
12. Low flow and stop functions
1. Low-flow detection function
The pump will check the flow regularly by reducing the speed for
a short time. If there is no or only a small change in pressure, this
means that there is low flow.
The speed will be increased until the stop pressure (actual
se 0.5 x
Δ
H) is reached and the pump will stop after a few
seconds. The pump will restart at the latest when the pressure
has fallen to the start pressure (actual setpoint - 0.5 x
Δ
H).
If the flow in the off period is higher than the low-flow limit, the
pump will restart before the pressure has fallen to the start
pressure.
When restarting, the pump will react in the following way:
1. If the flow is higher than the low-flow limit, the pump will return
to continuous operation at constant pressure.
2. If the flow is lower than the low-flow limit, the pump will
continue in start/stop operation. It will continue in start/stop
operation until the flow is higher than the low-flow limit. When
the flow is higher than the low-flow limit, the pump will return
to continuous operation.
Operating conditions for the stop function
It is only possible to use the stop function if the system
incorporates a pressure sensor, a non-return valve and a
diaphragm tank.
Note
Note
If the Dry Pump Function setting is changed to
“Warning” or “OFF” the drive will not stop motor
operation and there is a risk of damage to the
pump. This is not recommended by Grundfos.
Note
Note
Changing this parameter may cause the Dry-Run
function to stop working and therefore put the
pump at risk for damage. Use caution when
making adjustments to this parameter.
Caution
The non-return valve must always be installed
before the pressure sensor.