Barrier Or Flushing Liquid Connections Of Dead-End Solutions; Checking The Direction Of Rotation; Pit Installation; Bypass With Pressure-Relief Valve - Grundfos NK Serie Montage- Und Betriebsanleitung

The auxiliary unit requires additional monitoring, e.g. dry-running
protection, to ensure supply of barrier or flushing liquid.
Warning
The responsibility for checking the functions of
the dry-running protection, such as flow rate,
sealing pressure and temperature of the barrier
or flushing liquid rests with the installer/owner.
8.3 Barrier or flushing liquid connections of dead-end
solutions
Fig. 2 Examples of double seal arrangements with dead-end
solutions
Warning
The barrier or the flushing liquid must be
connected to pipe connection number 2 for the
examples in fig. 2. Pipe connections 1 and 3 must
be plugged. See fig. 3.
1
2
Fig. 3 Pipe connections

8.4 Checking the direction of rotation

Warning
Never check the direction of rotation by starting
the pump - not even for a short period - unless
the pump and auxiliary unit have been filled with
liquid. This is to prevent temperature rises
resulting from contact between rotating and
stationary components, and to protect the shaft
seal against dry-running.

8.5 Pit installation

Warning
Provide adequate ventilation if the pump is
installed in a pit.

8.6 Bypass with pressure-relief valve

Warning
Operation against a closed discharge valve or a
shut-off element may cause overheating and is
not allowed. This can be avoided by installing a
bypass with a pressure-relief valve. Observe the
minimum flow rate. See section 3. Related
installation and operating instructions.

8.7 Monitoring of bearing condition

Heavy-duty bearings are prepared for vibration measurement by
means of the shock pulse method (SPM). The bearing brackets
have also tappings for Pt100 temperature sensors for continuous
monitoring of the bearing condition.

8.8 Earthing of pump housing

Fig. 4

9. Operating conditions

9.1 Maximum liquid temperature

The maximum liquid temperature depends on the temperature
class specified by customer and the shaft seal.
3
The illustration below shows the maximum surface temperature
of the pump as a result of maximum liquid temperature and
temperature rise in the shaft seal.
Fig. 5
The maximum surface temperature of the pump must be at least
5 °C lower than the maximum surface temperature of the
temperature class specified by the customer.
The maximum liquid temperature and the temperature class
specified by the customer are stated on the "key application data
sheet" supplied with the pump. See the example at the end of this
booklet.
A copy is filed by Grundfos and can be traced by means of the
product number and serial numbers on the pump nameplate.
Warning
The pump housing must be earthed.
Earthing point of pump housing.
Tighten to 80 ± 16 Nm.
Maximum surface temperature
Temperature class
T1
T2
T3
T4
T5
T6
T [°C]
Maximum surface temperature of
the pump
Temperature rise in the shaft seal
(calculated by Grundfos)
Maximum liquid temperature
Calculation of maximum surface temperature
[°C]
450
300
200
135
100
85
7