Grundfos CU 301 User guide

CU 301

GRUNDFOS INSTRUCTIONS

Installer’s manual

CONTENTS

Page

1. Constant-pressure control 3

1.1 Description 3

1.2 Function 3

1.3 System sizing 5

1.4 Positioning the pressure sensor 6

1.5 Precharge pressure setting 6

1.6 Pressure relief valve 6

2. Operating functions 7

2.1 On/off button 7

2.2 Indication of pump operation 7

2.3 Pressure setting 7

2.4 Button locking 8

3. Alarm functions 8

3.1 Service alarm 8

3.2 Dry-running protection 9

4. Position of LEDs and fuse 10

5. CU 301 with R100 11

5.1 Menu OPERATION 14

5.1.1 Pressure setting 14

5.1.2 Operating mode 14

5.1.3 Alarm 14

5.2 Menu STATUS 15

5.2.1 Operating mode 15

5.2.2 Actual pressure 15

5.2.3 Speed 15

5.2.4 Temperature 15

5.2.5 Power input and power consumption 15

5.2.6 Operating hours and number of starts 16

5.3 Menu INSTALLATION 16

5.3.1 Sensor 16

5.3.2 Choice of sensor 16

5.3.3 Maximum pressure setting 16

5.3.4 Automatic restart 17

5.3.5 Dry-running stop 17

5.3.6 Maximum speed 17

5.3.7 Buttons on CU 301 17

5.3.8 Indication of pump operation 18

5.3.9 Number 18

6. Fault finding 19

6.1 Service 19

7. Technical data 23

7.1 Electrical connection 24

7.1.1 Mains supply 25

7.1.2 Pump supply 25

7.1.3 Pressure sensor 25

1. Constant-pressure control

1.1 Description

The system maintains a constant pressure within the

maximum pump performance in spite of a varying

water consumption.

Fig. 1 shows an example of an installation with con-

stant-pressure control.

Fig. 1

1.2 Function

The pressure is registered by means of the pressure

sensor, which transmits a signal to the CU 301. The

CU 301 adjusts the pump performance accordingly

by changing the pump speed.

Mains borne signalling:

The communication between the CU 301 and the

pump is effected via the power supply cable.

This communication principle is called mains borne

signalling (or power line communication). Using this

principle means that no additional cables to the

pump are required.

The communication of data is effected by means of a

high-frequency signal transmitted to the power sup-

ply cable and led into the electronics unit by means

of signal coils incorporated in the motor and the

CU 301 respectively.

Fig. 2 shows the principle of mains borne signalling

between the CU 301 and the pump.

Fig. 2

TM01 7862 4999

Pos. Description

1 CU 301

2 Diaphragm tank

3 Pressure sensor

4 SQE pump

TM01 8495 1703

Pos. Description

1 Supply to the electronics

2 Signal coils

3 Capacitor

4Electronics for the control of the com-

munication

5 On/off button

6 Sensor signal

7 Electricity supply

8 Communication signals

R 100

CU 301

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 according-

ly 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

Note: When the pressure is dropping 0.1 bar/s or

faster, the pump will start immediately.

If a diaphragm tank of 8 litres is used, the pump will

start at a flow rate of approx. 0.18 m³/h.

Note: If a larger tank is used, the flow must be

higher before the pump starts.

Consumption up to 0.18 m³/h:

The pump will start when the pressure has dropped

to 0.5 bar below the pressure setting.

The pump will run until the pressure is 0.5 bar above

the pressure set.

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 until a small pressure

drop is registered. This pressure drop indicates that

water is consumed 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

System limits:

Even though the CU 301 is controlling the pressure

within ±0.2 bar, 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 pipe-

work, but, typically, they will lie between 0.5 and

1 bar.

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

fig. 5.

Fig. 5

A = Pressure set

TM01 8545 0400

Pressure

Time

Low flow

High flow

TM01 8546 0400TM01 8634 0500

Pressure

Time

Flow detection

10 s10 s

Controlling

±0.2 bar Dynamic

variations

±0.5 bar

Pressure

Start

-0.5 bar

Stop

+0.5 bar

m³/h

0.18

low

Flow

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 min-1 to 10,700

min-1, see fig. 6.

It is recommended to follow the guidelines below:

Fig. 6

The following must be fulfilled:

1. Min. head at no flow < static head + system pres-

sure.

2. Max. head at max. flow > dynamic head + system

pressure.

Max. head at max. flow and min. head at no flow can

be found in the following table:

TM01 8547 0400

H [m]

Q [m³/h]

Max. head at max. flow

Min. head at no flow

Pump curve

at 10,700 min-1

Pump curve

at 3,000 min-1

Qmax

Pump type

Min. head

at Q = 0 m³/h,

3,000 min-1

Max. head

at Q = Qmax,

10,700 min-1

[m] / [feet] [m] / [feet]

SQE 1 - 35 18 / 59 29 / 86

SQE 1 - 50 28 / 91 44 / 131

SQE 1 - 65 37 / 121 59 / 177

SQE 1 - 80 46 / 151 75 / 222

SQE 1 - 95 56 / 184 90 / 270

SQE 1 - 110 65 / 213 105 / 315

SQE 1 - 125 74 / 243 120 / 360

SQE 1 - 140 81 / 266 136 / 405

SQE 1 - 155 92 / 302 151 / 450

SQE 2 - 35 19 / 62 35 / 105

SQE 2 - 55 29 / 95 54 / 164

SQE 2 - 70 38 / 125 71 / 215

SQE 2 - 85 47 / 154 88 / 267

SQE 2 - 100 56 / 184 108 / 328

SQE 2 - 115 66 / 217 128 / 390

SQE 3 - 30 15 / 49 26 / 75

SQE 3 - 40 24 / 79 42 / 123

SQE 3 - 55 31 / 102 56 / 164

SQE 3 - 65 39 / 128 70 / 205

SQE 3 - 80 47 / 154 84 / 246

SQE 3 - 95 55 / 180 98 / 287

SQE 3 - 105 62 / 203 113 / 328

SQE 5 - 15 7.7 / 25 11 / 36

SQE 5 - 25 15 / 49 23 / 77

SQE 5 - 35 23 / 75 36 / 117

SQE 5 - 50 30 / 98 48 / 159

SQE 5 - 60 38 / 125 61 / 200

SQE 5 - 70 45 / 148 73 / 240

SQE 7 - 15 8.6 / 28 9 / 33

SQE 7 - 30 18 / 59 23 / 82

SQE 7 - 40 27 / 89 37 / 126

1.4 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

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 bigger. This, of course,

depends on the piping. However, old and furred-up

piping may cause inconvenience due to friction loss.

Example: A person is in the shower. Tap 2 is

opened. The increased flow will cause pressure loss

in the pipe, and even though the CU 301 is keeping

the pressure constant at the pressure sensor, the

person in the shower will feel the pressure loss.

If the pressure sensor is placed closer to the shower

tap, the CU 301 will increase the pressure when the

flow is increased. Then the pressure at the shower

and tap 2 will be kept constant, but the pressure at

tap 1 will be increased.

Therefore, it is recommended that the pressure sen-

sor be positioned as close to the places of consump-

tion as possible.

1.5 Precharge pressure setting

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 8 litres.

Use the values in the following table:

Note: If the precharge pressure is higher than the

pressure setting, the system will not be able to con-

trol 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. In such cases, it is recommended to

use a larger diaphragm tank, e.g. a tank of double

size.

1.6 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 [bar] Precharge pressure [bar]

21.4

2.5 1.8

32.1

3.5 2.5

42.8

4.5 3.2

53.5

Tap 1 Tap 2

2. Operating functions

2.1 On/off button

Fig. 8 shows the on/off button of the CU 301.

Fig. 8

The green and red indicator lights in the on/off button

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.

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

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

TM01 7860 4701

Indication Description

Greenindicatorlight

permanently on. The system is operational.

Greenindicatorlight

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.

Zielona dioda

Czerwona dioda

bar

5.0

4.5

4.0

3.5

3.0

2.5

2.0

Green indi

cator light

Red indicator

light

TM01 8328 4701TM01 8329 4701

bar

5.0

4.5

4.0

3.5

3.0

2.5

2.0

bar

5.0

4.5

4.0

3.5

3.0

2.5

2.0

bar

5.0

4.5

4.0

3.5

3.0

2.5

2.0

Indication of pressure setting:

The system pressure set is indicated by a yellow

indicator light, which is permanently on.

Setting range: 2, 2.5 ... 5.0 bar.

Arrow-up button:

When this button is pressed, the system pressure

setting is increased in steps of 0.5 bar.

Arrow-down button:

When this button is pressed, the system pressure

setting is decreased in steps of 0.5 bar.

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,

the pressure setting may change.

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

When the buttons are locked, the indicator light is

permanently on, see fig. 11.

For further information, see section 5.3.7 Buttons on

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 exceed-

ed, the indicator light for service alarm is permanent-

ly on, see fig. 12.

Fig. 12

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 6.1 Service.

TM01 8330 4701

bar

5.0

4.5

4.0

3.5

3.0

2.5

2.0

TM01 8327 4701

bar

5.0

4.5

4.0

3.5

3.0

2.5

2.0

3.2 Dry-running protection

The purpose of the dry-running protection is to pro-

tect the pump in case of insufficient water flow.

The dry-running protection makes the conventional

dry-running protection unnecessary.

No additional cables to the motor are required.

The dry-running protection will be active after

30 seconds’ operation.

The dry-running alarm is activated when the load has

been below the minimum power limit for an accumu-

lated time of 5 seconds.

The motor is stopped and the dry-running indicator

light is permanently on, see fig. 13, pos. A.

Fig. 13

Restarting:

After 5 minutes (factory setting), or the period set by

means of the R100 display 5.3.4 Automatic restart,

the motor will restart automatically.

TM01 8329 4701

Possible cause Remedy

Thepumpperformance

is too high compared to

the borehole yield.

Replace the pump with

a smaller one.

Reduce pump perform-

ance using the R100

display 5.3.6 Maxi-

mum speed.

Borehole filter is

blocked. Borehole service is re-

quired.

bar

5.0

4.5

4.0

3.5

3.0

2.5

2.0

4. Position of LEDs and fuse

Fig. 14

TM01 8537 1703

Pos. Indication Description

1 +24 V overload Permanent red light when the internal 24 VDC supply is overloaded.

2 +24 V Permanent green light when the internal 24 VDC supply is OK.

3 +10 V Permanent green light when the internal 10 VDC supply is OK.

4 +5 V Permanent green light when the internal 5 VDC supply is OK.

5 9 indicator lights:

• Control indicator • Flashing green light when the pump control is working correctly.

• Min. speed • Permanent yellow light when the pump is running at minimum speed,

3,000 min-1.

• Max. speed • Permanent yellow light when the pump is running at maximum

speed, 10,700 min-1.

• Sensor defective *) • Permanent red light when the sensor signal is out of signal range.

• Overload *) • Permanent red light when the motor load exceeds the stop limit, see

section 7. Technical data.

• Overtemperature *) • Permanent red light when the motor temperature exceeds the stop

limit, see section 7. Technical data.

• Speed reduction *) • Permanent red light when the pump speed is reduced, see section

7. Technical data.

• Voltage alarm *) • Permanent red light when the supply voltage is out of range, see

section 7. Technical data.

• No contact to pump *) • Permanent red light when communication between the CU 301 and

the pump is impossible.

*) Press the on/off button to reset the alarm indication.

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