GB - 27/63
9 TROUBLESHOOTING
Problem
Cause
Solution
Electrical wiring incorrect
Get the operator to check the electrical connection
against the wiring diagram contained in the terminal
board box.
Power supply voltage unsuitable
Check that the power supply voltage, measured at
the motor’s terminals, is /- 10% of the
nominal voltage.
The unit does not start
The impeller is stuck
Get the operator to repair the unit
The suction filter is clogged
Get the operator to clean or replace the cartridge
Frequency wrong (for units powered via an
inverter)
Correct the frequency
No or insufficient air flow
Profile of the impeller blades modified (due to
deposits on the profile)
Get the operator to clean the impeller, check if it is
worn and, if necessary, replace it.
Incorrect rotation direction
Get the operator to invert the rotation direction by
switching two of the electrical power supply
conductors.
No or insufficient pressure
differential
Leaks in the plant
Identify the leak and seal
Electrical wiring incorrect
Get the operator to check the electrical connection
against the wiring diagram contained in the terminal
board box.
Drop in mains supply voltage
Get the operator to reinstate the power supply
voltage at the terminals at the admissible values
The suction filter is clogged
Get the operator to clean or replace the cartridge
The unit has accumulated deposits inside
Get the operator to clean the inside of the unit
Current absorption
exceeding the admissible
value
The unit is operating at a pressure and/or
vacuum that exceeds the admissible value
Adjust the system and/or the regulating valve to
lower pressure differentials.
The unit is operating at a pressure and/or
vacuum that exceeds the admissible value
Adjust the system and/or the regulating valve to
lower pressure differentials.
The suction filter is clogged
Get the operator to clean or replace the cartridge
The unit has accumulated deposits inside
Get the operator to clean the inside of the unit
Suction and/or delivery piping obstructed.
Get the operator to remove any obstructions
High delivery air
temperature
Suction air temperature exceeds 40°C
(+104°F)
Use heat exchangers to reduce the suction air
temperature
The soundproofing is damaged
Get the operator to replace the soundproofing
The impeller scrapes against the casing.
- The unit is operating at a pressure and/or
vacuum that exceeds the admissible value
Reduce the pressure differentials in the plant
- Reduction of assembly play due to internal
deposits (dust, impurities in the pipes, process
residues, etc.)
Get the operator to clean the inside of the plant
Bearing worn
Get the operator to replace the bearing
Anomalous noise
Unit’s installation position unsuitable
Do not fit structures (tanks, steel plating, etc.) on the
unit that can transmit or amplify noise
The impeller is damaged
Get the operator to replace the impeller
The impeller has accumulated deposits
Get the operator
to clean the inside of
the unit
Unit fixing without anti-vibration supports
Get the operator to fix the unit with anti-vibration
supports
Rigid connection to the plant
Get the operator to fit flexible hoses between the unit
and the piping
Abnormal vibrations
Bearing on the blower or motor side defective
Get the operator to replace the bearing
Defective silencer gaskets
Get the operator to clean or replace the gaskets
Leaks in the unit
Defective cover gaskets
Get the operator to clean or replace the gaskets
The term “operator” means: A qualified person appointed to install, operate, set, clean, repair or move a unit or to carry out
maintenance work on it.
