Maintenance And Service; Cleaning The Cu331Sp; Service Parts And Service Kits; Fault Finding - Grundfos CU331SP Installation And Operating Instructions Manual

Pressure sensor
Pump with non return valve
Fig. 23 Position of the pressure sensor and diaphragm tank
Diaphragm tank
The stop function requires a diaphragm tank of a certain minimum
size. The tank must be installed as close as possible after the
pump and the precharge pressure must be 0.7 x actual setpoint.
Recommended diaphragm tank size:
Rated flow rate of pump
3
[gpm (m /h)]
0-26 (0-6)
27-105 (7-24)
If a diaphragm tank of the above size is installed in the system,
the factory setting of ΔH is the correct setting.
If the tank installed is too small, the pump will start and stop too
often.

13. Maintenance and service

13.1 Cleaning the CU331SP

Keep the cooling fins and fan blades clean to ensure sufficient
cooling of the CU331SP.

13.2 Service parts and service kits

For further information on service parts and service kits, visit
www.grundfos.us > website> WebCAPS.
16
Diaphragm tank
Typical diaphragm tank size
[gallon (L)]
2 (7.5)
4.4 (16.7)

14. Fault finding

14.1 Warning and alarm list

Code and display text
Too high leakage
1
current
2 Mains phase failure
3 External fault
16 Other fault
32 Overvoltage
40 Undervoltage
48 Overload
49 Overload
55 Overload
57 Dry running
Too high CU331SP
64
temperature
89 Sensor 1 outside range
Setpoint signal outside
96
range
155 Inrush fault
241 Motor phase failure
1)
In case of an alarm, the CU331SP will change the operating
mode depending on the pump type.
2)
Warning is reset in display 3.20.

14.2 Resetting of alarms

In case of fault or malfunction of the CU331SP, check the alarm
list in menu OPERATION. The latest five alarms and latest five
warnings can be found in the log menus.
Contact a Grundfos technician if an alarm occurs repeatedly.
14.2.1 Warning
The CU331SP will continue the operation as long as the warning
is active. The warning remains active until the cause no longer
exists. Some warnings may switch to alarm condition.
14.2.2 Alarm
In case of an alarm, the CU331SP will stop the pump or change
the operating mode depending on the alarm type and pump type.
See 14.1 Warning and alarm list.
Pump operation will be resumed when the cause of the alarm has
been remedied and the alarm has been reset.
The CU331SP has an automatic reset function for all alarms
(except "Locked Alarm" as listed above.) The automatic reset
time is 10 seconds for all alarms except Dry-Run. The Dry-run
alarm will reset after 30 minutes.
Status
Operat- Reset-
ing mode ting
●
Stop Man.
●
Stop Aut.
●
Stop Man.
●
Stop Aut.
●
Stop Man.
●
- Aut.
●
Stop Aut.
●
- Aut.
●
Stop Aut.
●
Stop Aut.
●
Stop Man.
●
Stop Aut.
●
- Aut.
●
Stop Aut.
●
Stop Aut.
●
Stop Aut.
● 1)
Aut.
● 1)
Aut.
●
Stop Aut.
●
- Aut.
●
Stop Aut.