Datasheet

ENGLISH
Reversed direction of rotation.
Overloadedfilter.
Inlet turbulence in the same direction of
rotation as the impeller.
Change of sections, tight and close bends,
sudden widening or bends which do not
allow the dynamic inlet pressure to be nor-
mally recovered.
Check the electrical connection. Check the
winding connection on the motor terminal box.
Cleanorreplacethefilter.
Installflowstraighteners.
Design error; change or replace the circuit.
9.4 Airflowratetoohigh.
A the nominal rotation
speed, this causes
the fans with forward
curved blades and with
radial blades to draw
too much current.
Rotation speed too high.
Estimated circuit load losses too high.
Wrong direction of rotation of the impeller
Air leaks or open access doors, poorly ma-
nufactured or badly installed pipes or com-
ponents, bypass shutters not fully closed
Check the power voltage and, if needs be,
rectify it. Check the drive ratio, if needs be,
rectify it.
Partly close the shutters and/or reduce speed
until the required performance is achieved.
Check the direction of rotation. A reversed,
curvedorflatbladeimpellerwhichturnsinthe
reverse direction of rotation operates like an
impeller with forward curved blades and this
wouldcauseanexcessiveflowrate,anddraw
too much power. If this is case, restore the
correct direction of rotation.
Check the system by replacing the non confor-
ming components.
9.5 Pressure too low Rotation speed too low.
Reversed direction of rotation.
Flow rate higher than the design value due
to incorrect circuit size and/or air temperatu-
re different from the temperature considered
in the circuit design.
Damaged impeller.
See 9.3
See 9.3
Change the drive ratios and/or replace the fan,
replace or adapt the circuit.
Check the impeller and, if needs be, replace it
with a genuine part.
9.6 Air pulses. Thefanoperatesatalmostzeroflowrate
conditions
Unstableflow,obstructionsorbadinlet
connection which creates unstable air inlet
conditions (vortexes).
Alternateflowdisconnectionandreconnec
tion at a diverging channel walls.
Change the circuit and/or replace the fan.
Redesigntheinletbyplacingdeflectors,clean
and/or restore the inlet.
Redesign the circuit and/or replace the fan.
9.7 Reduced performance
after a period of sati-
sfactory operation.
Loss in the fan upstream and/or downstre-
am circuit.
Damaged impeller.
Check the circuit and restore its original condi-
tions.
Check the impeller and, if needs be, replace it
with a genuine part.
9.8 Too much noise. Nor-
mally, all fans generate
noise, but this should
Too many revolutions are required to achie-
ve the required performance.
Use of soundproofed casings and/or sound
dampers. Replace the fan with a larger fan able
to give the same performance or with a lower
Pag. 21