3
4.4 Duct connection (alterna-
tive)
ACL fans are prepared for circular duct
connections on the outlet side.
The duct may need to be adapted prior to
connection, e.g. the outlet side may need
to be shortened to make room for the dif-
fuser.
If the existing duct has a different diam-
eter than the diffuser, an adapter must be
fitted.
Systems with high vibration levels or ex-
acting performance requirements must
be provided with expansion joints be-
tween the fan and duct. The fan should
not be used to support the duct.
4.5 Electrical connection
Electrical connection must be made by
an authorised electrician in accordance
with current legislation. Power should
be connected direct to the frequency con-
verter. See figure 6. Connections should
be made in accordance with frequency
converter wiring diagrams. Note that the
fan cable is screened. It must be connect-
ed in such a way that the screen remains
unbroken.
If an external frequency converter is to be
used, its interference filter must meet
current requirements and regulations.
After connecting the fan, check that the
direction of impeller rotation complies
with the arrow plate on the fan housing.
Alternatively, the fan can be installed
without frequency converter. In such sit-
uations, the fan should be connected via
a terminal box or plug socket. Note! A
switch must be installed in the immedi-
ate vicinity of the fan.
5. Start-up
5.1 Before start-up
Before start-up, check that the fan has
been installed correctly. The section in
which the fan is installed and the adjoin-
ing duct should be checked and cleaned
of dirt, foreign matter and tools before
the fan is started.
Also ensure that the electrical connec-
tions fulfil applicable requirements, that
any protective grilles on the fan outlet
side are correctly fitted, and that the di-
rection of impeller rotation complies
with the arrow plate (check by briefly
starting the fan).
5.2 Motors with
Δ
/Y starter
The relay must be set to the calculated
time.
5.3 Start-up procedure
Staring the fan
1
Start the fan
2
Check that no abnormal sound oc-
curs.
3
Check that the vibration level is nor-
mal. At operating speed, fan vibration
must not exceed 7 mm/s rms meas-
ured radially at two points with 90°
offset and at the free shaft end of the
motor. Otherwise, the fan must be re-
balanced.
Operation at vibration levels higher
than 18 mm/s rms is inadvisable if vi-
bration dampers have been used. See
ISO 2954 – Requirements for instru-
ments for measuring vibration severity
.
4
After thirty minutes of operation,
check that the fan operates normally.
6. Maintenance
6.1 Safeguards prior to inspec-
tion and maintenance
Before inspecting or servicing the fan, it
must be switched off and disconnected
from the electrical system. Safeguards
must be taken to prevent the fan from re-
starting unintentionally.
6.2 Fan housing
As standard, the fan housing requires no
maintenance other than cleaning.
If the housing is painted, the surface
should be checked regularly and re-
paired where necessary.
6.3 Impeller
The impeller (rotor unit) is supplied with
blade pitch factory adjusted to the re-
quired operating conditions (pressure
and air flow) and actual fan speed. To en-
sure vibration-free operation, the impel-
ler has been carefully balanced in this po-
sition.
Vibration during operation is usually
caused by dust or dirt accumulating on
the hub and blades, and can normally be
corrected by cleaning. Should this not be
the case, technical assistance should be
called in immediately as continued vi-
bration will shorten the service life of the
blades and motor bearings.
6.4 Motor
Normally, only the motor bearings re-
quire maintenance. This should be per-
formed as described in the maintenance
instructions for electric motors.
6.5 Detaching the motor
Before detaching the motor, disconnect
the power supply to the fan.
Remove rod from top of end plate. Loos-
en mount from cross supports and pull
fan housing away from panel until mo-
tor is free of panel opening.
Now loosen mount from rails on base.
Remove entire assembly (fan housing
plus mount) from rails and lay aside on
an even surface.
Remove motor cable (pos. 12) from mo-
tor.
Remove impeller centre screw (pos. 01),
centre disc (pos. 02) and hub cover (pos.
Figure 3. Fitting the sealing strip
Figure 4. Fully installed diffuser
