Grundfos CMV 3, Installation And Operating Instructions Manual

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En
gl
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12
9. Technical data
9.1 Enclosure class
• IP55 (standard)
• IPx5 (with motor drain plug removed).
9.2 Sound pressure level
The sound pressure level of the pumps is lower than
70 dB(A).
9.3 Ambient temperature
9.4 Maximum system pressure and
permissible liquid temperature
* At liquid temperatures below 0 °C (32 °F), higher
motor outputs may be needed due to increased
viscosity, for instance if glycol has been added to
the water.
9.5 Minimum inlet pressure
You can calculate the minimum inlet pressure "H" in
metres head required during operation to avoid
cavitation in the pump from the following formula:
If the calculated value of "H" is positive, the pump
can operate with a maximum suction lift of "H"
metres.
If the calculated value of "H" is negative, a minimum
suction head of "H" metres is required during
operation to avoid cavitation.
Example
p
b
= 1 bar.
Pump type: CM 3, 50 Hz.
Flow rate: 4 m
3
/h.
NPSH (from fig. 5 , page 14 ): 3.3 metres head.
H
f
= 3.0 metres head.
Liquid temperature: 90 °C.
H
v
(from fig. 6 , page 15 ): 7.2 metres head.
H = p
b
x 10.2 - NPSH - H
f
- H
v
- H
s
[metres head].
H = 1 x 10.2 - 3.0 - 3.3 - 7.2 - 0.5 = -3.8 metres head.
This means that a suction head of 3.8 metres is
required during operation.
Pressure calculated in bar: 3.8 x 0.0981 = 0.37 bar.
Pressure calculated in kPa: 3.8 x 9.81 = 37.3 kPa.
9.6 Maximum inlet pressure
The actual inlet pressure plus the pressure when the
pump is operating against a closed valve must
always be lower than the maximum system pressure.
10. Disposal
This product or parts of it must be disposed of in an
environmentally sound way:
1. Use the public or private waste collection service.
2. If this is not possible, contact the nearest
Grundfos company or service workshop.
Maximum ambient
temperature
Liquid temperature
+55 °C (131 °F) +90 °C (194 °F)
Shaft seal AVBx AQQx
Permissible
liquid
temperature*
-20 to +40 °C
+41 to +90 °C -4 to 104 °F
105.8 to 194 °F
-20 to +90 °C -4 to 194 °F
Maximum
system
pressure
10 bar
6 bar 145 psi
87 psi
10 bar 145 psi
H = p
b
x 10.2 - NPSH - H
f
- H
v
- H
s
p
b
= Barometric pressure in bar.
The barometric pressure can be set to
1 bar.
In closed systems, p
b
indicates the
system pressure in bar.
NPSH = Net Positive Suction Head in metres
head. To be read from the NPSH
curves on pages
14 at the highest flow
rate the pump will be delivering.
H
f
= Friction loss in inlet pipe in metres
head.
H
v
= Vapour pressure in metres head.
See fig. 6 , page 15 .
t
m
= liquid temperature.
H
s
= Safety margin = min. 0.5 metres head.