Non-Return Valve; Electrical Connection - Grundfos ALPHA+ Montage- Und Betriebsanleitung

3.4 Non-return valve

If a non-return valve is fitted in the pipe system, see
sured that the minimum pump pressure is always higher than the closing
pressure of the valve.
3.5 Air separator pump
GRUNDFOS ALPHA+ pumps type A must be fitted with an au-
tomatic air vent. This must be fitted to the pump housing be-
fore priming.

4. Electrical connection

The electrical connection and protection should be carried out in accord-
ance with local regulations.
The earth terminal of the pump must be connected to earth.
The pump must be connected to an external mains switch with
a minimum contact gap of 3 mm in all poles.
• The pump requires no external motor protection.
• The operating voltage and frequency are marked on the pump name-
plate. Please make sure that the motor is suitable for the electricity
supply on which it will be used.
• Mains connection is to be carried out as shown in
• The green indicator light on the pump terminal box indicates that the
electricity supply has been switched on.
5. Start-up
Do not start the pump until the system has been filled with liquid and
vented. Furthermore, the required minimum inlet pressure must be avail-
able at the pump inlet, see section 7. Technical data . The system cannot
be vented through the pump.
As the pump is self-venting, it need not be vented before start-up.
When the inspection screw is slackened (see
liquid under high pressure may escape. Care should be taken
to ensure that the escaping liquid does not cause personal in-
jury or damage to other components.
The pump may be noisy, when first switched on, due to air remaining in
the chamber. This noise should cease after a few minutes running.
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, it must be en-
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