Xylem e-NSC, e-NSCF, e-NSCC - Manual (Page 20)

7.7 The electric pump starts, but the system's
residual current device (RCD) is activated
Cause Remedy
There is an ground
(earth) leakage.
Check the insulation of the electrical system
components.
7.8 The pump runs but delivers too little or no
liquid
Cause Remedy
There is air inside the
pump or the piping.
• Bleed the air
The pump is not correctly
primed.
Stop the pump and repeat the prime pro-
cedure.
If the problem continues:
• Check that the mechanical seal is
not leaking.
• Check the suction pipe for perfect
tightness.
• Replace any valves that are leaking.
The throttling on the deliv-
ery side is too extensive.
Open the valve.
Valves are locked in closed
or partially closed position.
Disassemble and clean the valves.
The pump is clogged. Contact the local sales and service repre-
sentative.
The piping is clogged. Check and clean the pipes.
The rotation direction of
the impeller is wrong
(three-phase version)
.
Change the position of two of the phases
on the terminal board of the motor or in
the electric control panel.
The suction lift is too high
or the flow resistance in
the suction pipes is too
great.
Check the operating conditions of the
pump. If necessary, do the following:
• Decrease the suction lift
• Increase the diameter of the suction
pipe
7.9 The electric pump stops, and then rotates
in the wrong direction
Cause Remedy
There is a leakage in one or both of the follow-
ing components:
• The suction pipe
• The foot valve or the check valve
Repair or replace the
faulty component.
There is air in the suction pipe. Bleed the air.
7.10 The pump starts up too frequently
Cause Remedy
There is a leakage in one or both of the fol-
lowing components:
• The suction pipe
• The foot valve or the check valve
Repair or replace the
faulty component.
There is a ruptured membrane or no air
pre-charge in the pressure tank.
See the relevant instruc-
tions in the pressure
tank manual.
7.11 The pump vibrates and generates too
much noise
Cause Remedy
Pump cavitation Reduce the required flow rate by partially closing
the on-off valve downstream from the pump. If the
problem persists check the operating conditions of
the pump (for example height difference, flow re-
sistance, liquid temperature).
Cause Remedy
The motor bear-
ings are worn.
Contact the local sales and service representa-
tive.
There are foreign
objects inside the
pump.
Contact the local sales and service representa-
tive.
For any other situation, refer to the local sales and service representa-
tive.
en - Translation of the original instructions
20 e-NSC Installation, Operation, and Maintenance Manual