Product Manual
Table Of Contents
- 1. SQ, SQE introduction
- 2. SQ, SQE applications
- SQ with pressure switch and pressure tank
- Constant-pressure control with CU 301, residential water supply
- Constant-pressure control with CU 301, irrigation
- Maintaining a constant water table
- Emptying or filling a tank
- Pumping from one tank to another
- Setting of operating parameters
- SQE with manual speed control
- 3. Performance range
- 4. SQ, SQE installation
- 5. Sizing and selection
- 6. Cable sizing
- 7. SQ, SQE curve charts
- 8. SQ, SQE technical data
- 9. SQ, SQE construction
- 10. CU331SP variable frequency drive
- 11. Accessories
- 12. SP introduction
- 13. SP product overview
- 14. SP construction
- 15. SP operating conditions
- 16. How to read the curve charts
- 17. SP curve charts and technical data
- 4" and larger wells
- SP 5S (5 gpm)
- SP 7S (7 gpm)
- SP 10S (10 gpm)
- SP 16S (16 gpm)
- SP 25S (25 gpm)
- SP 35S (35 gpm)
- SP 45S (45 gpm)
- SP 62S (62 gpm)
- SP 77S (77 gpm)
- 6" and larger wells
- SP 85S (85 gpm)
- SP 150S (150 gpm)
- SP 230S (230 gpm)
- SP 300S (300 gpm)
- 8" and larger wells
- SP 385S (385 gpm)
- SP 475S (475 gpm)
- 10" and larger wells
- SP 625S (625 gpm)
- SP 800S (800 gpm)
- SP 1100S (1100 gpm)
- 18. SP electrical data
- 19. Accessories
- 20. Energy consumption
- 21. Cables
- 22. Friction loss tables
- 23. Grundfos Product Center
CU331SP variable frequency drive
SQ, SQE, CU 331, and SP
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10. CU331SP variable frequency drive
Features
User interface
The user interface offers these possibilities:
• Local operation via a control panel with graphic
display where the menu structure is based on the
well-known system from Grundfos E-pumps.
• Monitoring of operating status via indicator lights
and signal relays.
• Display of alarm or warning and logging of the last
five alarms and warnings.
Functions
Control mode: Constant pressure
The CU331SP has only one control mode, Constant
pressure. The pressure is kept constant,
independently of the flow rate.
Start-up guide
The CU331SP has a start-up guide, which is launched
at the first power up. Parameters are set manually on
the basis of the installation. The start-up guide can be
repeated, if necessary.
Thanks to the start-up guide, the installer can quickly
set a few parameters and put the CU331SP into
operation.
Direction of rotation test
During start-up, the CU331SP automatically tests and
sets the correct direction of rotation without changing
the cable connections. The direction of rotation test
can be performed manually if it fails for any reason.
Dry-running protection
To protect the pump, the CU331SP will automatically
set up dry-run protection so that water shortage can be
detected. The dry-run alarm will automatically reset 30
minutes after the alarm is declared.
Low-flow stop function
The low-flow stop function is used for changing
between on/off operation at low flow rate and
continuous operation at high flow rate.
The low-flow stop function protects the pump and
saves energy.
Applications
For 4" or larger wells. Main applications:
• Domestic and light commercial water supply
• irrigation
• livestock watering
• water transfer.
System components
• Compact, efficient, and reliable variable frequency
drive
• rugged stainless steel pump end and proven,
reliable, 3-phase motor
• pressure sensor
• diaphragm tank (sold separately).
Fig. 21 CU331SP variable frequency drive and sensor
TM05 5801 4012