4
03).
Remove impeller using puller secured in
the two threaded puller holes in the hub
boss (pos. 05).
Loosen bolts in motor shell (pos. 06). Mo-
tor (pos. 11) and motor flange (pos. 10)
can then be removed.
When dismantling the fan, be careful not
to expose individual parts to impacts or
other forces that might damage the mo-
tor bearings or other fan parts.
6.6 Fitting the motor
After servicing is complete the motor
must be refitted. Check that the motor
flange (pos. 10) is correctly positioned
and that the motor shaft is concentrically
positioned in the fan housing before
tightening the bolts (pos. 06).
Refit impeller (pos. 04) on motor shaft
using puller secured in threaded hole on
motor shaft. Tighten impeller hub
against motor shaft collar.
Check that blade tip clearance is equal
around the entire circumference of the
housing. If this is not the case, adjust mo-
tor position in suspension system.
Then refit hub cover (pos. 03), centre disc
(pos. 02) and centre screw (pos. 01). It is
recommended that lock washers and
lock nuts be replaced when reassembling
the fan. Finally, reconnect motor cable
(pos. 12) to motor.
The fan must then be reinstalled against
the panel as previously described in sec-
tion 4. Installation.
To restart the fan, follow the procedure
described in section 5. Start-up.
6.7 Blade adjustment
The blade pitch is factory adjusted using
a special tool (fixture) to provide the out-
put required by the customer/order on
delivery.
If a different output is required, it is pos-
sible to alter blade pitch. This requires
knowledge of the motor load and the
max. permissible blade pitch in relation
to the motor rating (in case of blade pitch
increase).
Please contact Novenco before any such
adjustment of blade pitch. Special tools
for blade pitch adjustment and instruc-
tions for impeller balancing are available
from Novenco.
A brochure describing the blade pitch
tool and its use is available on request.
6.8 Fault finding
Possible operating faults are described in
the following.
Insufficient output
• Blocked air supply on inlet side
– Damper closed
– Duct blocked
– Supply fan (if any) stopped
– Motor defective
– Motor cut out
• Incorrect direction of impeller rota-
tion
Noise/vibration
• Bearings in electric motor defective
• Impeller out of balance
• Impeller worn/damaged
• Bolts/components loose
• Impeller blades have different pitch
• Fan operating in "stall" mode. This
may damage the system and should
be remedied immediately, see "Insuf-
ficient output”.
Sizes
Min.
Average
H
u
b
d
iam
ete
r
23
0,
330
and 38
0
400
0.6
1.2
500
0.5
1.4
560
0.6
1.5
630
0.6
1.7
710
0.7
2.0
800
0.8
2.2
900
0.9
2.5
Table 3. Blade tip clearance [mm]
Figure 5. Exploded drawing of ACL fan
01: Centre screw
02: Centre disc
03: Hub cover
04: Impeller
05: Hub boss
06: Screw for motor shell
07: Washer for motor shell
08: Motor shell
09: Fan housing
10: Motor flange
11: Motor
12: Motor cable
13: Metal lead-through
