Grundfos CU 301 User manual

CU 301
GRUNDFOS INSTRUCTIONS
Installation and operating instructions

LIMITED WARRANTY
Products manufactured by GRUNDFOS PUMPS CORPORATION (Grundfos) are
warranted to the original user only to be free of defects in material and workmanship
for a period of 24 months from date of installation, but not more than 30 months from
date of manufacture. Grundfos' liability under this warranty shall be limited to repair-
ing or replacing at Grundfos' option, without charge, F.O.B. Grundfos' factory or
authorized service station, any product of Grundfos' manufacture. Grundfos will not
be liable for any costs of removal, installation, transportation, or any other charges
which may arise in connection with a warranty claim. Products which are sold but
not manufactured by Grundfos are subject to the warranty provided by the manu-
facturer of said products and not by Grundfos' warranty. Grundfos will not be liable
for damage or wear to products caused by abnormal operating conditions, accident,
abuse, misuse, unauthorized alteration or repair, or if the product was not installed
in accordance with Grundfos' printed installation and operating instructions.
To obtain service under this warranty, the defective product must be returned to the
distributor or dealer of Grundfos' products from which it was purchased together
with proof of purchase and installation date, failure date, and supporting installation
data. Unless otherwise provided, the distributor or dealer will contact Grundfos or
an authorized service station for instructions. Any defective product to be returned
to Grundfos or a service station must be sent freight prepaid; documentation sup-
porting the warranty claim and/or a Return Material Authorization must be included
if so instructed.
GRUNDFOS WILL NOT BE LIABLE FOR ANY INCIDENTAL OR CONSEQUEN-
TIAL DAMAGES, LOSSES, OR EXPENSES ARISING FROM INSTALLATION,
USE, OR ANY OTHER CAUSES. THERE ARE NO EXPRESS OR IMPLIED WAR-
RANTIES, INCLUDING MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE, WHICH EXTEND BEYOND THOSE WARRANTIES DESCRIBED OR
REFERRED TO ABOVE.
Some jurisdictions do not allow the exclusion or limitation of incidental or conse-
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other rights which vary from jurisdiction to jurisdiction.
2

3
CU 301
Installation and operating instructions 4

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CONTENTS Page
1. Constant-pressure control 5
1.1 Description 5
1.2 Function 5
1.3 System sizing 7
1.4 SQE and SQE-NE 7
1.5 Positioning the pressure sensor 8
1.6 Precharge pressure setting 8
1.7 Pressure relief valve 8
2. Operating functions 9
2.1 On/Off button 9
2.2 Indication of pump operation 9
2.3 Pressure setting 9
2.4 Button locking 10
3. Alarm functions 10
3.1 Service alarm 10
3.2 Dry-running protection 11
4. Position of LEDs 12
5. CU 301 with R100 13
5.1 Menu OPERATION 15
5.1.1 Pressure setting 15
5.1.2 Operating mode 15
5.1.3 Alarm 15
5.2 Menu STATUS 16
5.2.1 Operating mode 16
5.2.2 Actual pressure 16
5.2.3 Speed 16
5.2.4 Temperature 16
5.2.5 Power input and power consumption 16
5.2.6 Operating hours and number of starts 17
5.3 Menu INSTALLATION 17
5.3.1 Sensor 17
5.3.2 Choice of sensor 17
5.3.3 Maximum pressure setting 17
5.3.4 Automatic restart 18
5.3.5 Dry-running stop 18
5.3.6 Maximum speed 18
5.3.7 Cut-in speed 18
5.3.8 Buttons on the CU 301 19
5.3.9 Indication of pump operation 19
5.3.10 Number 19
6. Print 20
7. Troubleshooting 21
7.1 Service 21
8. Technical data 25
8.1 Electrical connection 26
8.1.1 Mains supply 27
8.1.2 Pump supply 27
8.1.3 Pressure sensor 27
9. Pressure sensor voltage chart 28
10. Disposal 29
Prior to installation, read these installation
and operating instructions. Installation and
operation must comply with local regula-
tions and accepted codes of good prac-
tice.

5
1. Constant-pressure control
The control unit CU 301 is for use only with Grundfos
SQE pumps incorporating electronic power factor
correction (PFC).
1.1 Description
The system maintains a constant pressure within the
maximum pump performance in spite of a varying
water consumption.
The CU 301 is designed for wall mounting only.
Fig. 1 Example of a system with constant-
pressure control
1.2 Function
The pressure is registered by means of the pressure
sensor, which transmits a 4-20 mA signal to the
CU 301. The CU 301 adjusts the pump performance
accordingly to maintain constant pressure by chang-
ing the pump speed.
Mains borne signalling
The communication between the CU 301 and the
pump is via the power supply cable.
This communication principle is mains borne signal-
ling (or power line communication). Using this princi-
ple means that no additional cables to the pump are
required.
The communication of data is effected via a high-fre-
quency signal transmitted to the power supply cable
and led into the electronics unit by means of signal
coils incorporated in the motor and the CU 301
respectively.
In situations where multiple CU 301 pump power
cables are run parallel in wiring trays or conduit and
less than 10-12 inches apart, the possibility for
undesired communication between units exists.
When this occurs, intermittent or continuous
"No contact" is typically seen. Other unexpected
errors may also be seen.
Refer to section 5.3.10 for further instructions.
Fig. 2 Principle of mains borne signalling
TM01 7862 4999
Pos. Description
1 CU 301
2 Diaphragm tank (2 gal.)
3 Pressure sensor
4 SQE pump
1
4
2
3
TM01 8495 1606
Pos. Description
1 Supply to the electronics
2 Signal coils
3 Capacitor
4Electronics for the control of
the communication
5 On/Off button
6 Sensor signal
7 Mains supply
8 Communication signals
R 100
CU 301
15
2
4
3
6
7
8
CU 301

6
When does the pump start?
The pump starts as a consequence of
• a high flow or
• a low pressure or
• a combination of both.
To ensure that the pump is started when water is
consumed, a flow detection is required. The flow is
detected via pressure changes in the system. When
water is consumed, the pressure will drop accord-
ingly depending on the size of the diaphragm tank
and the water flow:
• at a low flow, the pressure will drop slowly.
• at a high flow, the pressure will drop quickly.
See fig. 3.
Fig. 3 Pressure changes in relation to flow
Note: When the pressure is dropping 1.4 psi/s or
faster, the pump will start immediately.
With a diaphragm tank of 2 gal., the pump will start at
a flow rate of approx. 0.8 gpm.
Note: If a larger tank is used, the flow must be higher
before the pump starts.
Consumption up to 0.8 gpm
The pump will start when the pressure has dropped
to 7 psi below the pressure setting.
The pump will run until the pressure is 7 psi above
the pressure setting.
Flow detection
During pump operation, i.e. when water is con-
sumed, the CU 301 will adjust the pump speed to
maintain a constant pressure. In order to stop the
pump when no water is consumed, the CU 301 per-
forms flow detection every 10 seconds.
The pump speed is reduced and pressure is read.
A pressure drop indicates that water is being con-
sumed and the pump speed is resumed, see fig. 4.
If the pump speed can be reduced without any pres-
sure drop being registered, this indicates that no
water is consumed. The diaphragm tank will be filled
with water and the pump will be stopped.
Fig. 4 Flow detection every 10 seconds
during operation
System limits
Even though the CU 301 is controlling the pressure
within ±3 psi, bigger pressure variations may occur in
the system. If the consumption is suddenly changed,
e.g. if a tap is opened, the water must start flowing
before the pressure can be made constant again.
Such dynamic variations depend on the pipework,
but, typically, they will lie between 7 and 14 psi.
If the desired consumption is higher than the quantity
the pump is able to deliver at the desired pressure,
the pressure follows the pump curve as illustrated in
the far right of fig. 5.
Fig. 5 Possible pressure variations during
constant-pressure operation
A = Pressure setting
TM01 8545 0400
Pressure
Time
Low flow
High flow
TM01 8546 0400TM01 8634 0500
Pressure
Time
Flow detection
10 s10 s
Controlling
±3 psi
Dynamic
variations
±7 psi
Pressure
Start
-7 psi
A
Stop
+7 psi
gpm
0.8
F
low
Flow

7
1.3 System sizing
To ensure the correct function of the system, it is
important that the pump is of the right type.
During operation, the CU 301 controls the pump
speed within the range from 3,000 rpm to 10,700
rpm, see fig. 6.
It is recommended to follow the guidelines below.
Fig. 6 Pump curves at 3,000 rpm and
10,700 rpm
A: Minimum head at no flow.
B: Maximum head at rated flow.
The following must be fulfilled:
• Minimum head at no flow < static head + system
pressure.
Comment: If this is not fulfilled, the pressure may
exceed the pressure set on the CU 301.
• Maximum head at rated flow > dynamic head +
system pressure.
Comment: If this is not fulfilled, the pressure may
fall below the pressure set on the CU 301.
Maximum head at rated flow and minimum head at
no flow can be found in the following sections.
1.4 SQE and SQE-NE
TM01 8547 0400
H [ft]
Q [gpm]
B
A
Pump curve
at 10,700 rpm
Pump curve
at 3,000 rpm
Qrated flow
Pump type
Min. head
at 0 gpm,
3,000 rpm
Max. head
at rated flow,
10,700 rpm
[feet] [feet]
5 SQE-90 12 104
5 SQE-140 18 161
5 SQE-180 24 218
5 SQE-230 31 275
5 SQE-270 37 332
5 SQE-320 43 389
5 SQE-360 49 446
5 SQE-410 55 503
5 SQE-450 61 560
10 SQE-110 12 102
10 SQE-160 17 158
10 SQE-200 23 214
10 SQE-240 29 270
10 SQE-290 34 326
10 SQE-330 40 382
15 SQE-70 10 80
15 SQE-110 4 121
15 SQE-150 19 161
15 SQE-180 24 202
15 SQE-220 29 242
15 SQE-250 33 283
15 SQE-290 38 323
22 SQE-40 5 35
22 SQE-80 9 75
22 SQE-120 14 115
22 SQE-160 18 155
22 SQE-190 23 195
22 SQE-220 27 235
30 SQE-40 5 31
30 SQE-90 11 78
30 SQE-130 16 125
10 SQE-100 NE 10 96
10 SQE-140 NE 15 134
10 SQE-180 NE 20 173
10 SQE-220 NE 25 212
10 SQE-260 NE 30 251
10 SQE-300 NE 34 290
10 SQE-340 NE 39 329
22 SQE-40 NE 35 290
22 SQE-80 NE 39 322
22 SQE-110 NE 42 353
22 SQE-140 NE 46 385
22 SQE-180 NE 50 417
22 SQE-210 NE 54 448

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1.5 Positioning the pressure sensor
Pressure losses often cause inconvenience to the
user. The CU 301 keeps the pressure constant in the
place where the pressure sensor is positioned, see
fig. 7.
Fig. 7 Pressure sensor position
In fig. 7, tap 1 is placed close to the pressure sensor.
Therefore, the pressure will be kept nearly constant
at tap 1, as the friction loss is small. At the shower
and tap 2, the friction loss is greater. This, of course,
depends on the piping.
Therefore, it is recommended that the pressure sen-
sor be positioned as close to the places of consump-
tion as possible.
1.6 Precharge pressure setting
The CU 301 is designed to work with a 2 gal. dia-
phragm tank.
The precharge pressure of the diaphragm tank must
be set to 70% of the pressure setting in order to use
the tank to the limit of its capacity. This is of course
especially important when the tank volume is limited
to 2 gal.
Use the values in the following table.
Prechange pressure is measured with 0 psi in the
pipeline:
Note: If the precharge pressure is higher than the
pressure setting, the system will have difficulty con-
troling the pressure.
If the user wants to adjust the pressure without
changing the precharge pressure of the diaphragm
tank, the precharge pressure must be equal to the
lowest pressure setting used. This means that the
control will work but that the pressure fluctuations
might increase.
1.7 Pressure relief valve
In order to provide protection against the possibility
of an overpressurization, a pressure relieve valve
should be installed down stream of the well head.
The setpoint of the pressure relief valve should be at
least 30 psi above the pressure setting, see section
2.3.
If a relief valve is installed, it is recommended that its
discharge be plumbed into an appropriate drainage
point.
TM01 7862 4999
Setting
[psi] Precharge pressure [psi]
40 28
50 35
60 42
70 49
80 56
90 63
100 70
Tap 1 Tap 2
Pressure sensor

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2. Operating functions
2.1 On/Off button
Fig. 8 On/Off button
The green and red indicator lights in the On/Off but-
ton indicate pump operating condition as follows:
* If the On/Off button has been used to stop the
pump, this button must also be used for restarting.
Any alarm indication can be reset by pressing the
On/Off button.
If the On/Off button is pressed for more than 5 sec-
onds, the pump is started, irrespective of any active
fault/alarm indications and sensor signals.
When the On/Off button is released, the pump will
stop, if the alarm still exists.
IMPORTANT
Setting this button to the OFF position DOES
NOT remove power from the pump. Before ser-
vicing the pump, remove power at the service
breaker.
2.2 Indication of pump operation
On the graphical illustration on the CU 301 front, the
riser pipe shows running light when the pump is
operating. When the pump is not operating, none of
the indicator lights are on, see fig. 9.
Fig. 9 Indication of pump operation
The indication of pump operation can be changed by
means of the R100.
Possible settings:
• "Running light" during pump operation
(factory setting).
• "Constant light" during pump operation.
2.3 Pressure setting
The two arrow buttons on the CU 301 front are used
for the pressure setting, see fig. 10.
Fig. 10 Pressure setting and indication
TM02 4169 1606
Indication Description
Green indicator light
permanently on The system is operational.
Green indicator light
off
The system is not opera-
tional.
Red indicator light
permanently on
Pump has been stopped by
means of the On/Off button.*
Red indicator light
flashing
The CU 301 is communicat-
ing with the R100.
PSI
100
90
80
70
60
50
40
Green indi-
cator light
Red indica-
tor light
TM02 4170 1606TM02 4171 1606
PSI
100
90
80
70
60
50
40
PSI
100
90
80
70
60
50
40
PSI
100
90
80
70
60
50
40

10
Indication of pressure setting
The system pressure set is indicated by a yellow
indicator light, which is permanently on.
Setting range: 40-100 psi.
Arrow-up button
When this button is pressed, the system pressure
setting is increased in steps of 10 psi.
Arrow-down button
When this button is pressed, the system pressure
setting is decreased in steps of 10 psi.
2.4 Button locking
The buttons on the CU 301 can be locked/unlocked
by pressing the two arrow buttons simultaneously for
5 seconds or via the R100 remote control.
Note: When the arrow buttons are used for locking,
take care not to inadvertently change the pressure
setting.
Use the following procedure:
1. Set the pressure one step up.
2. Press the arrow-down button as the first one
when pressing the two buttons.
Fig. 11 Button lock indication
When the buttons are locked, the indicator light is
permanently on, see fig. 11.
For further information, see section 5.3.8 Buttons on
the CU 301.
3. Alarm functions
The CU 301 continuously receives operating data
from the pump. The alarm functions indicated on the
CU 301 front are described in the following sections.
3.1 Service alarm
If one or more factory-set alarm values are
exceeded, the indicator light for service alarm is per-
manently on, see fig. 12.
Fig. 12 Service alarm indicator
Possible alarms:
• Sensor defective
• Overload
• Overtemperature
• Speed reduction
• Voltage alarm
• No contact to pump.
The possible alarms and how to identify them and
make the relevant corrections are described in sec-
tion 7.1 Service.
TM02 4172 1606
PSI
100
90
80
70
60
50
40
TM02 4173 1606
PSI
100
90
80
70
60
50
40