Grundfos CU 301 Instrucciones De Instalacion Y Operacion página 9

Figure shows the principle of mains borne signalling
(power line communication) between CU 301 and
the pump.
CU 301
1
2
3
8
7
Fig. 6 Principle of mains borne signalling
(power line communication)
Pos. Description
1 Supply to the electronics
2 Signal coils
3 Capacitor
Electronics for the control of the
4
communication
5 On/off button
6 Sensor signal
7 Power supply to the pump
8 Communication signals
5
4
Grundfos GO
Remote
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When does the pump start
The pump starts as a consequence of the following:
• high flow
• low pressure
• combination of both.
To ensure that the pump starts when water is
consumed, flow detection is required. The flow is
detected via pressure changes in the system. When
water is consumed, the pressure drops accordingly
depending on the size of the diaphragm tank and the
water flow:
• at a low flow, the pressure drops slowly.
• at a high flow, the pressure drops quickly.
See fig. 7.
Pressure
Low flow
Fig. 7
When the pressure drops 1.4 psi/s or faster, the
pump starts immediately.
If a diaphragm tank of 2 gal is used, the pump starts
at a flow rate of approximately 0.8 gpm. If a larger
tank is used, the flow must be higher before the
pump starts.
Consumption up to 0.8 gpm
The pump starts when the pressure drops to 7 psi
below the pressure setting.
The pump runs until the pressure is 7 psi above the
pressure set.
In low flow situations, the flow cannot be
detected and the system is running on
pressure only.
Time
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