Pumps - AERMEC NSB Serie Manual Tecnico

12. 1 SELECTION PUMPS
NOTE
for each NSB model the choice of
the pump is unique, this means that
the pump will always be the same for
all circuits making up the selected
model. In the presence of a second
reserve pump, the pump is switched
over manually by acting on the
selector switch inside the electric
control board.
Premise: the last character of the
selected model indicate show many
hydraulic circuits make up the machi-
ne. For models from 3002 to 4802,
according to that mentioned above,
the pump will be selected by dividing
the total water flow rate stated in the
technical data table by 2 (last cha-
racter in the marketing name). The
same procedure must also be applied
to models from 5003 to 7203. In this
case the total flow rate is divided by
3 (last character in the name). For all
remaining models the water flow rate
is that indicated in the technical data
table.
12. 1 .2
Example of pump selection
NSB 3202L (2 hydraulic circuits)
Requested useful delivery pressure
300 kPa.
Nominal water flow rate = 105.950
m3/h
Loss of nominal load = 30 kPa per
circuit.
Procedure:
1. Divide the nominal flow rate by 2 (2
circuits) 105.950/2 = 52.975 m3/h
≈ 53 m3/h
With the water flow rate obtained (53
m3/h) enter the graphics as shown at
the side, finding out, that to satisfy the
requirements of a useful delivery pres-
sure of 300 kPa pump J is available
that offers:
Pump J = 345 kPa
kW absorbed by 8
2. At this point in order to have the
useful delivery pressure for the plant,
just subtract the loss of load from the
evaporator from the pump delivery
pressure:
kPa pump (PJ) – Loss of nominal load
345kPa - 30kPa = 315 kPa of useful
delivery pressure to the plant. (15 kPa
higher than the request).
28

PUMPS

12
10. 1 . 1 Pumps available
field kit pump/s
00 Without pumping assembly
PA with pump A
PB with pump A and reserve pump
PC with pump C
PD with pump C and reserve pump
PE with pump E
400
kPa
PJ
350
PG
300
PE
250
PC
200
PA
150
100
50
20 30 40
20
kW
15
10
5
0
20 30 40
Example
kPa
kW
field kit pump/s
PF with pump E and reserve pump
PG with pump G
PH with pump G and reserve pump
PJ with pump J
PK with pump J and reserve pump
50 60 70 80 90
50 60 70 80 90
Water flow m 3 /h
Water flow m 3 /h
100 110
PJ
PG
PE
PC
PA
100 110