8.2 List of faults
Fault description
Cause
Remedy
Personnel
Fan does not start
Motor connected incor-
rectly
Check the connections
Skilled qualified
electrician
No power
Check the power supply
Skilled qualified
electrician
One or two live wires
have failed
Check the power consumption
Skilled qualified
electrician
Belt not assembled cor-
rectly
Ensure that the belt is positioned correctly
Instructed person
Electric motor
switches off
Electric motor is too
warm, thermal contact
triggers
Allow the electric motor to cool down.
Depending on the control module, the fan
either automatically starts up again or it has
to be restarted.
Skilled qualified
electrician
Impeller sluggish? Bearing damaged?
Replace the impeller or motor bearing if nec-
essary
Instructed person
Electrical connection is
faulty
Are all of the live wires loaded equally and
connected?
Check the power consumption / direction of
rotation
Skilled qualified
electrician
Motor is overloaded
Does the operating point match the sizing?
Replace the motor with a more efficient one
Skilled qualified
electrician
Fan does not reach
the nominal speed
Motor starting torque is
too low for ramping up
Replace the motor or provide a start-up
system
Skilled qualified
electrician
Air volume flow rate
is incorrect
Direction of rotation of
fan is incorrect
A centrifugal fan always blows air out, even if
it is rotating in the incorrect direction
Change the direction of rotation by switching
two live wires on the terminals
Skilled qualified
electrician
Impeller no longer suit-
able because the casing
has been changed
The blades are then curved in the incorrect
direction as there are different impellers for
clockwise and anticlockwise rotation.
Installation of an impeller that is suitable for
the type of casing
Instructed person
Impeller blocked
Switch off the fan and remove the blockage.
Observe the accident prevention regulations.
Instructed person
Impeller defective
Switch off the fan. Dismantle the impeller and
replace it with a new one.
Instructed person
The impeller speed is
incorrect
Motor speed incorrect?
Check the motor or belt drive, replace if nec-
essary
Instructed person
Ratio of the belt pulley diameter is incorrect?
Replace the belt drive
Instructed person
V-belt slip is too high?
Tension the V-belt
Instructed person
Frequency inverter parameterised incor-
rectly?
Skilled qualified
electrician
Faults
List of faults
Centrifugal fans REH; RZH; BVREH; BVRA
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