Checking The Direction Of Rotation - Grundfos S2 Instrucciones De Instalación Y Funcionamiento

Horizontal pumps do not normally require special considerations
for the start level if the inlet pipe is designed to prevent air
pockets from forming. See fig. 18.
Fig. 18 Horizontal, dry installation (H)
Minimum stop level
Minimum distance between bottom of pit and
lowest part of inlet pipe
Minimum start level
S is the minimum stop level. The minimum distance S above the
inlet pipe is required to avoid the formation of vortices at the inlet
pipe and thus to avoid air being sucked into the pump. Air in the
pumped liquid may cause vibrations, cavitation and loss of pump
performance.
G is the minimum start level of a dry-installed, vertical pump if no
other actions are taken to ensure that the pump housing is filled
with pumped liquid when the pump is started. Other possible
actions:
• Use a vacuum pump to suck liquid into the pump housing; this
requires an isolating valve on the outlet side.
• Install a non-return valve in the outlet pipe after the first
startup; this will prevent the draining of the pump housing
between running periods.
Eccentric reducer
S = D
1
F = 0.5 x D
1
G = D
p

5.2 Checking the direction of rotation

Only start an unsubmerged pump for a few seconds
to check the direction of rotation.
A label with an arrow on the pump housing indicates the correct
direction of rotation. The direction of rotation is clockwise when
seen from the drive end.
DANGER
Crushing of hands
Death or serious personal injury
- Do not touch the pump when starting it up.
Make sure that the bottom of the pit is clear of debris
before startup to avoid material being sucked into the
impeller.
Installation types S (submerged without cooling jacket), C
(submerged with cooling jacket) and ST (submerged in vertical
column pipe without cooling jacket):
Proceed as follows:
1. Lift the pump approximately. 0.8 - 2 in (2-5 cm) from the
ground or base using the lifting chain and a crane.
2. Start and run the pump for a few seconds.
3. Observe the jerk of the pump. If the pump jerks counter-
clockwise, the direction of rotation is correct.
In case the direction of rotation is wrong, interchange two phases
in a power cable.
Installation types D (dry vertical) and H (dry horizontal):
Check the duty point.
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