Starting Up The Pump; Shaft Seal Run-In Period; Start/Stop; Reference Readings Of Monitoring Equipment - Grundfos NB Serie Instrucciones De Instalación Y Funcionamiento

11.4 Starting up the pump

1. Open the isolating valve on the inlet side of the
pump completely 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.
Warning
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 the cold liquid.
4. When the pipes have been filled with liquid,
slowly open the isolating valve on the outlet side
until it is completely open.
If the pump is fitted with a motor with an
output selected on the basis of a specific
Caution maximum flow rate, the motor may be
overloaded if the differential pressure is
lower than anticipated.
5. Check the overload by measuring the motor
current consumption and comparing the value
with the rated current stated on the motor
nameplate. In case of overload, throttle the valve
on the outlet side until the motor is no longer
overloaded.
6. Always measure the motor current consumption
during startup.
At the moment of start, the input current of
the motor is up to six times higher than the
Note
full-load current stated on the motor
nameplate.
30

11.5 Shaft seal run-in period

The seal faces are lubricated by the pumped liquid,
meaning that there may be a certain amount of
leakage from the shaft seal. When the pump is
started for the first time, or when a new shaft seal
has been installed, a certain run-in period is required
before the leakage is reduced to an acceptable level.
The time required for this depends on the operating
conditions, i.e. every time the operating conditions
change, a new run-in period will be started.
Under normal conditions, the leaking liquid will
evaporate. As a result, no leakage will be detected.
Liquids such as kerosene will not evaporate, and
drops will be visible, but this is not a shaft seal
failure.
Mechanical shaft seals are precision components. If
the mechanical shaft seal of a recently installed
pump fails, this will normally happen within the first
few hours of operation. The main cause of such
failures is improper installation of the shaft seals
and/or mishandling of the pump during installation.

11.6 Start/stop

Maximum number of starts per
Frame
size Number of poles
2
56-71 100
80-100 60
112-132 30
160-180 15
200-225 8
250-315 4
11.7 Reference readings of monitoring
equipment
We recommend that you take initial readings of these
parameters:
• vibration level - use SPM (shock pulse method)
measuring points
• inlet and outlet pressure - use pressure gauges.
The readings can be used as reference in case of
abnormal operation.
hour
4 6
250 350
140 160
60 80
30 50
15 30
8 12