Maintaining The Motor; Lubrication Of Motor Bearings; Applying Sealant To Plugs; Taking The Product Out Of Operation - Grundfos NB Installation And Operating Instructions Manual

End suction pumps equipped with mechanical shaft
seals are matched to the operating conditions for
which the pump was sold. Observe the following
precautions to avoid shaft seal damage and achieve
maximum shaft seal life.
Do not run the pump dry or against a
closed valve. Dry running will cause shaft
seal failure.
Do not exceed the temperature or
pressure limitations for the mechanical
shaft seal in use.

10.3 Maintaining the motor

It is important to keep the motor clean in order to
ensure adequate ventilation.
• Check the motor at regular intervals.
• If the pump is installed in a dusty environment,
check and clean it regularly.

10.4 Lubrication of motor bearings

10.4.1 MG motors
The bearings of motors up to 11 kW are greased for
life and require no lubrication.
The bearings of motors of 11 kW and up must be
greased in accordance with the indications on the
motor nameplate.
10.4.2 Other motors
For other motor makes with grease nipples, lubricate
the motor according to the indications on the motor
nameplate. Grease specifications: See section
Bearing grease.
Related information
10.4.3 Bearing grease
10.4.3 Bearing grease
The lithium-based grease used should meets the
following specifications:
• NLGI class 2 or 3
• viscosity of basic oil: 70 to 150 cSt at +40 °C
• temperature range: -30 °C to +140 °C during
continuous operation.

10.5 Applying sealant to plugs

Remember to clean the threads and apply sealant to
the plug when assembling it.
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11. Taking the product out of operation

11.1 Protecting the pump during periods of
inactivity and frost
Pumps that are not being used during periods of frost
must be drained to avoid damage.
WARNING
Escaping liquid
Death or serious personal injury
‐
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.
1. Drain the pump by removing the drain plug.
M
E
Drain plug (E), priming and venting plug (M)
2. Do not tighten the priming plug or replace the
drain plug until the pump is to be used again.
3. If the pump is to be drained before a long period
of inactivity, inject a few drops of silicone oil on the
shaft at the bearing bracket. This will prevent the
shaft seal faces from seizing up.