Twin-Head Pumps; Master Pump And Slave Pump; Non-Return Valve; Insulation - Grundfos UPED 80-120 FZ Montageanleitung Und Bedienungsanleitung

4.4 Twin-head pumps

Twin-head pumps offer these operating modes:
• alternating operation
• standby operation
• synchronous operation
• single-pump operation.

4.4.1 Master pump and slave pump

The master pump will always be the pump to the
right when seen from the control box end and the
pump is pumping upwards. See fig. 3, pos. 1.
Master pump (1) and slave pump (2)
Fig. 3

4.5 Non-return valve

If a non-return valve is fitted in the pipe system
(fig. 4), it must be ensured that the minimum
discharge pressure is always higher than the closing
pressure of the valve. This is especially important in
proportional-pressure control mode (reduced head
at low flows).
Non-return valve
Fig. 4

4.6 Insulation

If the pump is insulated without using Grundfos
insulating kits, it must be ensured that the
differential-pressure and temperature sensor in the
pump housing is not covered.

4.7 Frost protection

If the pump is not being used during periods of frost,
the necessary steps must be taken to prevent frost
bursts.

5. Electrical connection

The electrical connection and protection must be
carried out according to local regulations.
Warning
Never make any connections in the
pump control box unless the power
supply has been switched off for at
least 5 minutes. The indicator light
must be off. See fig. 6, pos. 21.
The earth terminal of the pump must be
earthed.
The pump must be connected to an
external mains switch with a minimum
contact gap of 3 mm in all poles.
Earthing or neutralisation can be used
for protection against indirect contact.
Megging must be carried out as
described in section 10. Megging.
If the pump is connected to an electric
installation where an earth leakage
circuit breaker (ELCB) is used as an
additional protection, this circuit
breaker must trip out when earth fault
currents with DC content (pulsating
DC) and smooth DC earth fault currents
occur.
The earth leakage circuit breaker must
be marked with these symbols:
• The pump requires no external motor protection.
• Check that the supply voltage and frequency
correspond to the values stated on the pump
nameplate.

5.1 Ferrite core

Install the ferrite core as shown below.
Ferrite core installed
Fig. 5
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