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Installation and operating instructions Wilo-CronoNorm-NL, NLG
39
10.2
Causes and remedies
Error type:
1
2
3
4
5
6
7
8
Cause
Remedy
X
Counter pressure too high
• Check system for contaminants
• Reset the duty point
X
X
X
Pump and/or piping not completely
filled
• Bleed pump and fill suction line
X
X
X
Inlet pressure too low or suction head
too high
• Correct the fluid level
• Minimize resistances in the suction
line
• Clean filter
• Reduce suction head by installing
the pump lower
X
X
X
Sealing gap too large due to wear
• Exchange worn stationary wear ring
X
Incorrect direction of rotation
• Change the motor connection
phases
X
Pump is suctioning air or the suction
line is leaky
• Replace seal
• Check suction line
X
Supply line or impeller clogged
• Remove clog
X
X
Pump blocked by loose or jammed
parts
• Clean pump
X
Air enclosures in the piping
• Change the pipe layout or install a
bleed valve
X
Speed too low
• with frequency converter operation
• without frequency converter opera-
tion
• Increase frequency in the permissi-
ble range
• Check voltage
X
X
Motor running on 2 phases
• Check phases and fuses
X
X
Counter pressure of the pump too low • Readjust the duty point or adjust
the impeller
X
The viscosity or density of the fluid is
higher than the design value
• Check the pump dimensioning
(consult with the manufacturer)
X
X
X
X
X
Pump is stressed or the stuffing box
gland is inclined or tightened too
tightly
• Correct the pump installation
X
X
Speed too high
• Lower speed
X
X
X
Pump unit poorly aligned
• Correct alignment
X
Thrust too high
• Clean the relief bores in the impeller
• Check the condition of the station-
ary wear rings
X
Bearing lubrication not sufficient
• Check bearing, exchange bearing
X
Coupling distance not maintained
• Correct the coupling distance
X
X
X
Flow rate too low
• Maintain recommended minimum
flow rate
X
Housing screws not correctly tight-
ened or seal defective
• Check tightening torque
• Replace seal
X
Mechanical seal / stuffing box leaky
• Replace the mechanical seal
• Tighten the stuffing box or repack
X
Shaft sleeve (if present) worn
• Replace the shaft sleeve
• Repack the stuffing box
X
X
Imbalance of the impeller
• Rebalance the impeller
