Fault rectification
Troubleshooting and repairs only permissible when carried out by qualified electricians. Observe enclosed safety instructions.
Risk of skin burns in the vicinity of the blower caused by hot air medium, hot motor or hot housing. There is a danger to life near high-temperature blowers with airstream temperatures of up to 150 °C.
Before working on the centrifugal blower wait until it (motor, housing) has cooled sufficiently and the air medium has mixed with cold air and cooled to below 60 °C. The blower should then only be approached close up and then only be touched if you are certain that it has cooled down. This applies in particular to high-temperature blowers.
- Deactivate the mains fuse and fit a padlock to make sure it isn't reactivated.
- Wait until the blower has cooled down sufficiently and the impeller is stationary before removing the protection against accidental contact or touching the blower.
- Lock the impeller so that it cannot move any more. This protects you from unforeseen rotary movements, such as those which may be caused by air flows in the ventilation channel.
Blower does not switch on/does not run
Cause 1: No mains voltage, earth fault.
Measure: Check whether the power supply is guaranteed (mains fuse, motor connection).
Cause 2: Wiring not carried out correctly.
Measure: Check wiring → connection wiring diagram.
Cause 3: Thermal motor protection has triggered (motor is overheated).
Measure: Ensure that the air ways are free, remove foreign objects if necessary. Check room temperature. Check voltage. If necessary, install air filter in duct system.
Cause 4: The impeller is blocked or dirty.
Measure: Remove foreign objects or dirt.
Blower runs too slowly / volumetric flow too low
Cause 1: Impeller is rubbing
Measure: Remove foreign objects or dirt.
Cause 2: Deposits on the impeller and in the housing caused by dust in the air.
Measure: Install air filter in duct system. Ensure that air ways are free.
Cause 3: Air ways blocked.
Measure: Check that the air ways are free (supply/exhaust shutters, protective grille, filter).
Vibrations/unusual noises
Cause 1: Imbalance, impeller rubbing
Measure: Check impeller for damage, dirt or icing. Remove foreign objects and deposits on the impeller and in the housing. Ensure that air ways are free.
Cause 2: Bearing faulty/worn.
Measure: Replace unit.
Difficulty starting the blower
Cause 1: Inadequate supply voltage.
Measure: Check data on rating plate.
Cause 2: Fuses not suitable for start-up conditions.
Measure: Replace.
Cause 3: Incorrect assessment of moment of inertia and connector components.
Measure: Re-calculate moments of inertia and fit blower with a new motor if required.
Excessive power consumption (above value stated on rating plate).
Cause 1: Excessive speed.
Measure: Replace motor and/or resize system.
Cause 2: Air density higher than stated in the project data.
Measure: Replace motor and/or disc and/or resize system.
Cause 3: Blower running at too high a pressure.
Measure: Resize the system or change the blower type.
Cause 4: Motor running at below the normal speed.
Measure: Check supply voltage and correct if necessary. Check winding for defects and repair or replace if necessary.
Inadequate pressure
Cause 1: Throughput is higher than stated in the project data as a result of the wiring being rated incorrectly and/or temperatures other than those planned for.
Measure: Change gear ratios and/or replace blower, replace or adapt wiring.
Cause 2: Impeller damaged.
Measure: Check impeller and replace if necessary.
Air pulsations
Cause 1: Blower running at throughput values close to zero.
Measure: Change wiring and/or replace blower.
Cause 2: Unstable flow, blockage or poor intake connection result in unstable air inlet conditions (swirl).
Measure: Use deflectors to rearrange the intake, clean and/or reconstruct intake.
Cause 3: Flow alternates between detaching from and re-attaching to the walls of a diverging channel.
Measure: Rearrange the wiring and/or replace blower.
Power drop after acceptable operating period
Cause 1: Leaks in channel upstream of blower.
Measure: Check channel and re-establish initial conditions.
Cause 2: Impeller damaged.
Measure: Check impeller and replace if necessary.
The air being transported, mechanical parts, electrical noises etc. are causing excessive noise.
Cause 1: Too high a speed is needed to achieve the desired output.
Measure: Use sound-absorbing housing and/or sound absorber. Replace blower with a model with larger dimensions and the same output or with a lower peripheral speed.
Cause 2: Impeller scraping on housing.
Measure: Check and, if necessary, correct installation position of impeller and cables.
Cause 3: Bearings worn.
Measure: Check condition of bearings; if necessary lubricate or replace.
Cause 4: Rotor and stator not positioned centrally.
Measure: Check coaxiality; if necessary re-establish or replace electric motor.
Cause 5: Vibrations in the winding.
Measure: Can be reduced by using higher quality motors.
Cause 6: Installation in resonant surroundings.
Measure: Reposition blower or use sound-absorbing housing.
Excessive vibrations
Cause 1: Rotating parts imbalanced.
Measure: Check balance of impeller and, if necessary, restore to the prescribed values. Check alignment of drive and/or balance of washers. Check that shafts are straight.
Cause 2: Installation structure unsuitable: its natural frequency is close to the blower’s speed.
Measure: Use weights to increase and/or change natural frequency of installation structure.
Cause 3: Screw connections too loose.
Measure: Tighten.
Cause 4: Bearing defect.
Measure: Check bearing for wear and correct lubrication.