Minimum Flow Rate; Electrical Data; Frequency Of Starts And Stops; Dimensions And Weights - Grundfos CR Serie Instrucciones De Instalación Y Funcionamiento

5.6 Minimum flow rate

Due to the risk of overheating, do not use the pump at flows
below the minimum flow rate.
The curves below show the minimum flow rate as a percentage of
the rated flow rate in relation to the liquid temperature.
- - - - = air-cooled top.
Qmin
[%]
30
20
10
0
40 60 80 100 120 140 160 180
Fig. 5 Minimum flow rate
Caution
The pump must not run against a closed outlet valve.

5.7 Electrical data

See motor nameplate.

5.8 Frequency of starts and stops

Motor size
Maximum number of starts per hour
[kW]
≤ 2.2
3-4
5.5 - 11
18.5 - 22
30
37
45
55
75

5.9 Dimensions and weights

Dimensions: See fig. C, page 335.
Weights: See label on the packing.

5.10 Sound pressure level

See fig. D, page 336.

6. Installation

The pump must be secured to a horizontal, plane and solid
foundation by bolts through the holes in the base plate. When
installing the pump, follow the procedure below in order to avoid
damaging the pump.
Step
1
2
4 x ø
L
B
1
1
L B
2
2
8
t [°C]
250
100
50
40
90
50
80
50
50
Action
Arrows on the pump base show
the direction of flow of liquid
through the pump.
This information is stated on
page 335:
• port-to-port lengths
• dimensions of the base
• pipework connections
• diameter and position of
foundation bolts.
Step
3
3a
4
5
6
Action
You can install the pump
vertically or horizontally. CR,
CRN 120 and 150, 75 kW, only
vertically. However, the motor
must neither fall below the
horizontal plane nor be
installed upside down.
Make sure that an adequate
supply of cool air reaches the
motor cooling fan.
Motors above 4 kW must be
supported.
Additional support. As the
centre of gravity on the pump is
relative high, we recommend
that pumps installed on ships,
in areas with risk of earth
quake or in systems which has
to be moved are equipped with
additional support brackets.
You can fit the bracket from the
motor stool to the bulkhead of
the ship, a rigid wall in a
building or to a rigid part.
To minimise possible noise
from the pump, we advise you
to fit expansion joints on either
side of the pump.
Carry out the foundation or
installation as described in
section 6.1 Foundation.
Fit the isolating valves on
either side of the pump to avoid
draining the system if the pump
needs to be removed for
cleaning, repair or
replacement.
Always protect the pump
against backflow by means of a
non-return valve.
Install the pipes so that air
locks do not occur, especially
on the inlet side of the pump.
Fit a vacuum valve close to the
pump if the installation has one
of these characteristics:
• The outlet pipe slopes
downwards away from the
pump.
• There is a risk of siphon
effect.
• Protection against backflow
of unclean liquids is needed.