Twin-Head Pumps; Non-Return Valve; Frost Protection - Grundfos MAGNA 40-120 Montage- Und Betriebsanleitung

Fig. 2 Changing the control box position
Pos. Description
1 Inspection screw
2 Screw
3 Stator housing/control box
4 Rotor
5 T-key
6 O-ring

4.3 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
7.12.1 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. 3.
The automatic air vent is not supplied with the pump.
Fig. 3 Automatic air vent
8

4.4 Non-return valve

If a non-return valve is fitted in the pipe system,
see fig. 4, 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
5
mode (reduced head at low flows).
4
6
Fig. 4

4.5 Frost protection

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