Fault description
Cause
Remedy
Personnel
Air volume flow rate
is incorrect
Change the frequency inverter parameter
settings
The duct system pres-
sure losses are higher
than expected / calcu-
lated
At which operating point is the fan running?
Change the duct version; prevent turbulence
using baffle plates.
Increase the fan speed (note: do not exceed
the motor limit rating or the maximum fan
speed)
Instructed person
Is the operating point in the unstable range?
Resize and replace the fan
Open the bypass
Reduce pressure losses in the duct
Instructed person
Dampers or grilles in the
system are closed
Open the dampers or grilles
Instructed person
An object is obstructing
the airflow in the duct
Clean the duct / remove the obstruction
Instructed person
Vane controls are (parti-
ally) closed
Open the vane control
Instructed person
Filter is dirty
Clean or replace the filter
Instructed person
Fan is pumping
Fan is working in an
unfavourable character-
istic curve range
Reduce the system resistances.
Instructed person
Increased vibrations
Impeller imbalance due
to deposits
Please note that the system, consisting of
the impeller, crankshaft, belt pulleys and belt,
always has a residual imbalance, even if all
of the components are balanced!
Clean and rebalance the impeller
Instructed person
Belt pulleys have an
inadmissible unbalance
Rebalance the system
Instructed person
Belt knocking too much
Retention the belt
Instructed person
Vibration isolators are
assembled or positioned
incorrectly
Incorrectly selected vibration isolators can
result in the destruction of the fan!
Construct and assemble vibration isolators
correctly
Instructed person
Vibration isolators are
the wrong size
Replace the vibration isolators
Instructed person
Air noises
Direction of rotation is
incorrect
Change the direction of rotation by switching
two live wires on the terminals
Skilled qualified
electrician
Pulsating volume flow
rate
Increase the cross sections to improve the
passage of air
Install baffle plates
Instructed person
Is the operating point in an unstable range?
Implement measures to reduce the overall
pressure loss
Instructed person
Mechanical noises
Belt drive not tensioned
sufficiently
V-belts must be retensioned after a warm-up
time
Tension the V-belt
Instructed person
Faults
List of faults
Centrifugal fans REH; RZH; BVREH; BVRA
36