Grundfos LFE Instrucciones De Instalación Y Funcionamiento página 39

Diaphragm tank
The stop function requires a diaphragm tank of a certain minimum
size. 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 H 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 H.
17.3.9 Flow limit for the stop function
Flow limit for the stop function only works if the
system is not set up for flow switch.
In order to set at which flow rate the system is to go from
continuous operation at constant pressure to start/stop operation,
select among these four values of which three are preconfigured
flow limits:
• Low
• Normal
• High
• Custom.
The default setting of the pump is Normal, representing
approximately 10 % of the rated flow rate of the pump.
If a lower flow limit than normal is desired or the tank size is
smaller than recommended, select Low.
If a higher flow than normal is wanted or a large tank is used, set
the limit to High.
The value Custom can be seen in R100 but it can only be set by
means of the PC Tool E-products. Custom is for customized set-
up and optimizing to the process.
All manuals and user guides at all-guides.com
Typical diaphragm
tank size
[gal (liter)]
2 (7.6)
4.4 (16.7)
14 (53.0)
34 (128.7)
17.3.10 Sensor
62 (234.7)
Without sensor
(uncontrolled)
86 (325.5)
The setting of the sensor is only relevant in the case of controlled
operation.
Select among the following values:
•
•
•
H
Low
Normal High
Fig. 35 Three preconfigured flow limits, Low, Normal and High
Sensor output signal
0-10 V
0-20 mA
4-20 mA,
Unit of measurement of sensor:
3
bar, mbar, m, kPa, psi, ft, m /h, m
Sensor measuring range.
With pressure sensor
(controlled)
3
/s, l/s, gpm, °C, °F, %,
39