Installation On A Tank; Siphon Effect; Installation With Pressure-Loading Valve - Grundfos DMX 221 Instrucciones De Instalación Y Funcionamiento

2.1.2.3 Installation with pressure-relief valve
To protect the dosing pump and outlet line from excessive pressure, we recommend that you in-
stall a pressure-relief valve (6) in the outlet line.
6

2.1.2.4 Installation on a tank

When dosing non-degassing media with a viscosity similar to that of water, the pump can be
mounted on a tank.
• Observe the maximum suction lift.
• For sedimenting media, we recommend that you install an inlet line with a filter (14). Install
the foot valve 10 mm above the possible level of sedimentation.
14
Flooded suction
When dosing degassing media or media with a higher viscosity than that of water, the suction lift
will be reduced. In these cases, flooded suction may be required.
6

2.1.2.5 Siphon effect

The pressure at the outlet valve (p2) must always be at least 1 bar higher than the pressure at the
inlet valve (p1). If this is not the case, for example in an installation with open outflow or with floo-
ded suction, siphon effect may occur. To avoid the siphon effect, install a pressure-loading valve
(7) in the outlet line and an isolating valve (11) directly before the inlet valve.
p2
p1
11
7
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