Dry-Running Protection - Grundfos Hydro Multi-E Montage- Und Betriebsanleitung

6.6 Dry-running protection

The Hydro Multi-E must be protected against dry
Note
running.
The dry-running protection is described in two situations:
• Hydro Multi-E without emergency operation.
• Hydro Multi-E with emergency operation.
6.6.1 Hydro Multi-E without emergency operation
Types of dry-running protection:
• a pressure switch fitted in the suction manifold (factory-fitted
and set to 1.5 bar as standard)
• a level switch fitted in a water tank.
The dry-running protection has been connected to terminals 1
and 9 in pump 1.
Pump
1
PS
PS
Fig. 13 Pressure switch connected to pump 1
Pump
1
LS
Fig. 14 Level switch connected to pump 1
10
Pump
2
9: GND (frame)
1: Digital input
Pump
2
9: GND (frame)
1: Digital input
6.6.2 Hydro Multi-E with emergency operation
If the Hydro Multi-E control unit fails, terminals 1 and 9 will be
inactive. To ensure the dry-running protection, an additional
wiring has been made in the terminal box of pump 1 and between
the pumps. See also the wiring diagram in the breaker cabinet.
Pump
1
Pump 1
1 9
3 2
Fig. 15 Wiring of dry-running protection in emergency
operation
The short-circuit wire between terminals 2 and 3
has been removed (standard Hydro Multi-E).
Note
Instead the terminals 2 and 3 have been
configured to external fault.
Pump 3
Pump 2
3 2 3 2