Maintenance and service
ASD 531, Technical description, T 140 416 en
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9.4
Replacing units
Warning
Defective units such as the AMB 31, smoke sensor, air flow sensor and fan can only be replaced in the de-
energised state (with terminal block 1/2 and possibly 3/4 unplugged from the AMB 31).
9.4.1
Replacing the smoke sensor
The smoke sensor must be replaced if defective or if there is a dirt message.
To replace the smoke sensor proceed according to Sec. 6.3.
9.4.2
Replacing the aspirating fan unit
To replace the AFU 32 Aspirating Fan Unit, the AMB 31 main board must be removed. To do so, carefully unplug all the inter-
nal cable connections (including fan connection). The plug-in terminals 1 to 21 do not necessarily have to be unplugged. After
removing the retainer screws on the AMB 31 using a
Torx T10 screwdriver
, the AMB 31 can be lifted up toward the cable in-
feeds and the retaining screws on the aspirating fan unit are then accessible. To dismantle the aspirating fan unit, remove the
two screws
A
using a
Torx T15 screwdriver
To mount the new fan, proceed in the reverse sequence.
Important
: Before screwing on the replacement fan, the supplied
spacers must be inserted into their fastening holes.
The connection cable must be placed in
B
.
Warning
After replacing the aspirating fan unit, it is imperative to carry out a new initial reset (see Sec. 7.3.5).
Fig. 46 Removing the aspirating fan unit
A
B
B
