Vents VPVO Series User Manual page 14

The fan fails to reach the
required rotation speed due to
serious overheating of the fan
motor.
The fan motor runs at
overload capacity with current
consumption in excess of the
rated value.
The fan supplies more air than
expected.
The fan supplies less air than
expected.
Excessive noise or vibration both
inside the fan and in the circuit.
14
Fan motor overloaded.
Improper fan starting method.
The fan supplies more air than expected upon motor
capacity selection.
Wrong motor phasing. The impeller rotates in the
opposite direction of the arrow on the fan casing.
Air ducts clogged.
The resistance values used during the ventilation
network calculations are too conservative.
The cross section of air ducts increased and their
number reduced during the installation.
Wrong choice of the fan.
Wrong calculation of the ventilation network and
wrong selection of the fan.
The network resistance exceeds the design
calculations.
Wrong direction of the impeller rotation.
Air leak through a loose air duct connection.
Impeller or air duct contamination with foreign
objects or debris.
Loose screw connections.
No flexible joints between the fan and the ventilation
network on the suction and discharge sides.
Loose connection of valves and dampers to the air
ducts.
Impeller or air duct contamination with foreign
objects or debris.
Worn bearings.
Unstable power supply, unstable motor operation.
Eliminate the overload.
Use a soft starter or frequency converter to start the motor
(see "Asynchronous Electric Motor Starting Methods"
in the "Connection to power mains"
Measure network resistance. Throttle down the network
(add aerodynamic resistance to the air duct network).
If necessary, change the impeller rotation direction by
changing the phase sequence on the electric motor
terminals.
Clean the air duct or the impeller.
Check the air ducts for proper shape and cross section as
well as for any dampers present.
Throttle down the network (add aerodynamic resistance
to the air duct network).
Replace the fan with a unit of proper standard size.
Re-calculate the network parameters and select a
matching fan.
Re-arrange the ventilation network to decrease its
aerodynamic resistance.
If necessary, change the impeller rotation direction by
changing the phase sequence on the electric motor
(see the "Commissioning"
terminals
Eliminate the air leak. Seal the air duct connection.
Clean the impeller or the air ducts from foreign objects or
debris.
Check the screw connections for proper tightness.
Install flexible joints.
Tighten up the fasteners of valves and dampers.
Clean the impeller or the air ducts from foreign objects or
debris.
Replace the bearings.
Check the stability of power supply parameters and
electric motor operation.
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