Insulation Shells; Twin-Head Pumps; Non-Return Valve; Frost Protection - Grundfos MAGNA 2000-Serie Montage- Und Betriebsanleitung

4.3 Insulation shells

It is recommended to fit insulation
Note
shells to the pump.
• Insulation shells for pumps in heating systems
are supplied with the pump.
• Insulation shells for pumps in air-conditioning sys-
tems are accessories and must be ordered sepa-
rately. Please contact Grundfos.
The fitting of insulation shells will increase the pump
dimensions. See the dotted line on the dimensional
sketches on pages 291 and 293.
The insulation shells are only available for single-
head pumps.

4.4 Twin-head pumps

Twin-head pumps are supplied fitted with a GENI
module on each control box. The modules are
connected via a cable. The modules determine the
operating mode of the pump, see section
7.9.1 Control of twin-head pumps.
Twin-head pumps mounted in
horizontal pipes must be fitted with an
Caution
automatic air vent (Rp 1/4) in the upper
part of the pump housing, see fig. 1.
The automatic air vent is not supplied with the pump.
.
Fig. 1 Automatic air vent

4.5 Non-return valve

If a non-return valve is fitted in the pipe system,
see fig. 2, it must be ensured that the set minimum
discharge pressure of the pump is always higher
than the closing pressure of the valve. This is
especially important in proportional-pressure control
mode (reduced head at low flow).
Fig. 2 Non-return valve
10

4.6 Frost protection

If the pump is not used during periods of frost,
necessary steps must be taken to prevent frost
bursts.
Additives with a density and/or
kinematic viscosity higher than those/
Note
that of water will reduce the hydraulic
performance.

5. Electrical connection

The electrical connection and protection must be
carried out in accordance with local regulations.
Warning
The pump must be connected to an
external mains switch with a contact
separation of at least 3 mm in each
pole.
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
additional protection, this circuit
breaker must trip out when earth fault
currents with DC content (pulsating DC)
occur.
The earth leakage circuit breaker must
be marked with this symbol:
Warning
It must be possible to lock the mains
switch in the off position. Type and
requirements as specified in
EN 60204-1, 5.3.2.
• The pump requires no external motor protection.
• Check that the supply voltage and frequency
correspond to the values stated on the pump
nameplate.