Grundfos CU 301 Instrucciones De Instalación Y Operación página 9

CU 301
1
2
3
8
7
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
9 Grundfos GO Remote
When does the pump start
The pump starts as a consequence of the
following:
• high flow
• low pressure
• combination of both.
5
4
9
6
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.
1
4
Pos. Description
1 Pressure
2 Low flow
3 Time
4 High flow
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.
Flow detection
During pump operation, being when water is
consumed, CU 301 adjusts the pump speed to
maintain a constant pressure. In order to stop the
pump when no water is consumed, CU 301
performs flow detection every 10 seconds.
The pump speed is reduced until a small pressure
drop is registered. This pressure drop indicates
that water is consumed and the pump speed is
resumed. See fig. Flow detection every 10
seconds during operation.
2
3
9