Grundfos CRE Series Installation And Operating Instructions Manual page 28

Diaphragm tank volume
The stop function requires a diaphragm tank of a certain minimum
size. Set the size of the installed tank in this display.
In order to reduce the number of start/stops per hour or to reduce
the ∆H, a larger tank can be installed.
The tank must be installed immediately after the pump and the
precharge pressure must be 0.7 x actual setpoint.
Recommended diaphragm tank size:
Rated flow rate
of pump CRE pump
3
[gpm (m /h)]
0-26
1s, 1, 3
(0-5.9)
27 - 105
5, 10, 15
(6.1 - 23.8)
106 - 176
20, 32
(24.2 - 40)
177 - 308
45
(40.2 - 70.0)
309 - 440
64, 90
(70.2 - 99.9)
441 - 750
120, 150
(100 - 170)
If a diaphragm tank of the above size is installed in the system,
the factory setting of ΔH is the correct setting. If the tank installed
is too small, the pump will start and stop too often. This can be
remedied by increasing ΔH.
28
Analog input 1, 2 and 3, Function
Typical diaphragm
tank size
[gal (liter)]
2 (7.6)
4.4 (16.7)
The analog inputs can be set to these functions:
•
14 (53.0)
•
•
34 (128.7)
•
62 (234.7)
The number of available displays depends on the pump type. See
below.
86 (325.5)
Function (terminal)
Analog input 1, Function (4)
Analog input 2, Function (7)
Analog input 3, Function (14)
Not active
Feedback sensor
Ext. setpoint infl.
See section
11. External setpoint signal
Other function.
for further description.
CRE, CRIE,
CME CRNE, CRKE,
SPKE, MTRE
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