Checking The Direction Of Rotation; Starting Up The Pump - Grundfos NB Installation And Operating Instructions Manual

7.2.3 Priming the product in open systems where
the liquid level is below the pump inlet
1. If an isolating valve is fitted on the inlet side of the
pump, the valve must be fully open.
2. Close the isolating valve in the outlet pipe, and
tighten the priming and drain plugs.
M
E
Drain plug (E), priming and venting plug (M)
3. Connect a manual venting pump with the funnel
instead of a priming device.
4. Install a slide valve between the venting pump
and the centrifugal pump in order to protect the
venting pump against excessive pressure.
5. Once the slide valve at the manual venting pump
has been opened, vent the inlet pipe using short,
rapid pump strokes until the liquid runs out on the
outlet side.
6. Close the valve at the venting pump.

7.3 Checking the direction of rotation

Do not start the pump to check the
direction of rotation until it has been filled
with liquid.
The correct direction of rotation is shown by arrows
on the pump housing, and can visibly be checked by
means of the motor fan. Looking at the motor fan, the
direction of rotation must be clockwise.

7.4 Starting up the pump

1. Fully open the isolating valve on the inlet side of
the pump and leave the isolating valve on the
outlet side almost closed.
2. Start the pump.
3. Vent the pump during startup by loosening the air
vent screw in the pump head or pump head cover
until a steady stream of liquid runs out of the vent
hole.
Position of vent screw (A)
WARNING
Escaping liquid
Death or serious personal injury
‐
Pay attention to the orientation of
the vent hole to ensure that the
escaping liquid does not cause
personal injury or damage to the
motor or other components.
‐
In hot-liquid installations, pay
special attention to the risk of
personal injury caused by scalding
hot liquid.
‐
In cold-liquid installations, pay
special attention to the risk of
personal injury caused by cold
liquid.
4. When the pipes have been filled with liquid, slowly
open the isolating valve on the outlet side until it is
fully open.
A
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