9. Malfunctions, causes, and remedies
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9
9.5 System malfunctions
Malfunction Cause Remedy
Motor fails to start
when the operating
voltage is applied
o No operating voltage on motor
o Phase absent
• Check mains connection
• Check mains plug/cable and connect properly if necessary
• Check operating voltage on motor
• Check fuse
• Check motor circuit breaker
o Pump jammed
• Measure motor current If current is impermissibly high:
• Dismantle pump, crank by hand:
• if resistance is high, replace the pump.
o Motor jammed
• Measure motor current If current is impermissibly high:
• Dismantle motor, crank by hand:
• If resistance is high, replace the motor.
Pump motor runs
with difficulty and
at a low speed
o Sluggish pump
• Measure motor current If current is impermissibly high:
• Dismantle pump, crank by hand:
• if resistance is high, replace the pump.
Motor runs with
difficulty and at a
low speed
o Sluggish motor
• Measure motor current If current is impermissibly high:
• Dismantle motor, crank by hand:
• If resistance is high, replace the motor.
o Unsuitable lubricant
(see “Technical Data,” Chapter 3)
• Remove lubricant from entire system and dispose of lubricant in
the proper manner; fill system with suitable lubricant
o Pressure too high, pressure-regulating
valve is jammed or defective
• Check pressure-regulating valve and replace if necessary