Wilo MC Serie Instrucciones De Instalación Y Funcionamiento página 10

English
10. Defects - causes - remedies
WARNING! Electrical shock hazard!
Dangers caused by electrical energy must be ex-
cluded.
All electrical work must be performed after the
electrical supply has been switched off and se-
cured against unauthorized switching.
WARNING! Risk of scalding!
At high water temperatures and system pressure
close isolating valves before and after the pump.
First, allow pump to cool down.
Defects
Pump turns but no delivery
The pump vibrates
The pump overheats
The motor fails to run
10
Causes
The internal parts are obstructed by for-
eign bodies
Suction pipe obstructed
Air leaks in via suction pipe
The pump has lost prime
The suction pressure is too low; this is
generally accompanied by cavitation
noise
The pump turns the wrong way (three-
phase motor)
The supply voltage to the motor is too
low
The strainer is not under water
Loose on its foundation
Foreign bodies obstructing the pump
Pump is hard to turn
Incorrect electrical connection
Voltage too low
Foreign bodies obstructing the pump
Ambient temperature above +40°C
/104°F
No power
Pump seized
Remedies
Dismantle the pump and clean it
Clean all the pipes
Check the tightness of the whole pipe,
up to the pump, and make it tight
Fill the pump to re-prime. Check that the
foot valve is tight
Loss of head on suction or suction height
too great (check the NPSH of the pump
installed)
Interchange two phase wires on the
motor terminal block or circuit-breaker
to reverse the direction of rotation
Check the voltage on the terminals of the
motor and the cross-sections of the con-
ductors
Submerge the strainer (at least 20 cm); if
necessary, ballast the hose
Check the nuts of the stud bolts and
tighten them fully
Dismantle the pump and clean it
Check that the pump turns freely without
abnormal sticking
Check the connections to the pump
Check the voltage on the terminals of the
motor; it should be within ± 10 % of the
rated voltage
Dismantle the pump and clean it
The motor is designed to operate at an
ambient temperature of not more than
+40°C /104°F
Check the power supply
Clean the pump
WILO SE 09/2008