30
en - Original instructions
without forcing as far as it will go.
2.
Make a notch as reference on both half
couplings; see Figure 22.
3.
Rotate the same half coupling in the
opposite direction as far as it will go.
4.
Measure the distance between the two
notches: this will be the torsional
backlash.
Coupling
size
Maximum permitted
torsional backlash
ΔS
V
[mm]
68
5.5
80
5.0
95
6.0
110
7.0
125
8.0
140
8.0
160
8.0
If the torsional backlash exceeds the maximum
permitted limits, contact Xylem or the Authorised
Distributor for the replacement of the coupling.
6.2
Inspection checklist
Check the
coupling
Check the flexible elements
of the coupling. Replace the
relevant parts if there is any
sign of wear and check the
alignment.
Check the
mechanical
seal
Check for leaks on the
mechanical seals; if any are
detected, contact Xylem or
the Authorised distributor.
Checking the
bearing seals
Check correct seating of
axial seal rings mounted on
the shaft. Only gentle
contact of the sealing lip
shall be established.
Check for
quiet running
Check frequently for quiet
running of the pump with
vibration measurements
tools.
6.3 Disassemble and replace the
pump parts
For more information about spare parts and
assembly and disassembly of the pump,
contact Xylem or the Authorised Distributor.
Repair and/or maintenance of the pump must
only be carried out by Xylem or the Authorised
Distributor.
7 Troubleshooting
7.1 Troubleshooting for users
The main switch is on, but the pump unit does
not start.
Cause
Solution
The thermal
protector
incorporated in the
pump (if any) has
tripped.
Wait until the pump
has cooled down. The
thermal protector will
automatically reset.
The protective
device against dry
Check the liquid level
in the tank, or the
running has
tripped.
mains pressure.
The pump unit starts, but the thermal protector
trips a varying time after
Cause
Solution
There are foreign
objects (solids or
fibrous
substances) inside
the pump which
have jammed the
impeller.
Contact Xylem or the
Authorised Distributor.
The pump is
overloaded
because it is
pumping liquid
that is too dense
and viscous.
Check the actual
power requirements
based on the
characteristics of the
pumped liquid and then
contact Xylem or the
Authorised Distributor.
The pump runs but delivers too little or no
liquid.
Cause
Solution
The pump is
clogged.
Contact Xylem or the
Authorised Distributor.
The troubleshooting instructions of the
following tables are only for installation
personnel.
7.2 The main switch is on, but the
pump unit does not start
Cause
Solution
There is no power
supply.
•
Restore the
power supply.
•
Make sure all
electrical
connections to
the power supply
are intact.
The thermal
protector
incorporated in the
pump (if any) has
tripped.
Wait until the pump
has cooled down. The
thermal protector will
automatically reset.
The thermal relay
or motor protector
in the electric
control panel has
tripped.
Reset the thermal
protection.
The protective
device against dry
running has
tripped.
Check:
•
liquid level in the
tank, or the mains
pressure.
•
protective device
and its
connecting
cables.
The fuses for the
pump or auxiliary
circuits are blown.
Replace the fuses.
7.3 The pump unit starts, but the
thermal protector trips or the fuses
