3) Checking and measures to be taken
(a) Measures against noise
Check the items below when noise can be confirmed on wave shape or the error code in the item 1) is generated.
Items to be checked Measures to be taken
1Wiring of transmission and power lines
in crossing
2Wiring of transmission line with that of
other system in bundle
3Use of shield wire for transmission line
(for both indoor unit control and central-
ized control)
4Repeating of shield at the repeating of
transmission line with indoor unit
5Are the unit and transmission lines
grounded as instructed in the INSTAL-
LATION MANUAL?
6Earthing of the shield of transmission
line (for indoor unit control) to outdoor
unit
7Arrangement for the shield of transmis-
sion line (for centralized control)
Isolate transmission line from power line (5cm or more).
Never put them in a same conduit.
Wire transmission line isolating from other transmission line.
Wiring in bundle may cause erroneous operation like crosstalk.
Use specified transmission wire.
Type : Shield line CVVS/CPEVS
Wire diameter : 1.25mm2 or more
The transmission line is wired with 2-jumper system. Wire the
shield with jumper system as same for transmission line.
When the jumper wiring is not applied to the shield, the effect
against noise will be reduced.
Connect to ground as shown in the INSTALLATION MANUAL.
One point earthing should be made at outdoor unit.
Without earthing, transmission signal may be changed as the
noise on the transmission line has no way to escape.
For the shield earth of the transmission line for centralized con-
trol, the effect of noise can be minimized if it is from one of the
outdoor units in case of the group operation with different refrig-
erant systems, and from the upper rank controller in case the
upper rank controller is used.
However, the environment against noise such as the distance of
transmission line, the number of connecting sets, the type of
connecting controller, and the place of installation, is different for
the wiring for centralized control. Therefore, the state of the
work should be checked as follows.
a) No earthing
•Group operation with different refrigerant systems
One point earthing at outdoor unit
•Upper rank controller is used
Earthing at the upper rank controller
b) Error is generated even though one point earth is being con-
nected.
Earth shield at all outdoor units.
Connect to ground as shown in the user’s manual.
Checking for wiring method
Check for earthing
(b)When the wave height value of transmission wave shape is low, 6607 error is generated, or remote controller is
under the state of "HO."
8The farthest distance of transmission
line is exceeding 200m.
9The types of transmission lines are dif-
ferent.
;No transmission power (30 V) is being
supplied to the indoor unit or the remote
control.
AFaulty indoor unit/remote controller
Confirm that the farthest distance from outdoor unit to indoor
unit/remote controller is less than 200m.
Use the transmission wire specified.
Type of transmission line : Shield wire CVVS/CPEVS
Wire dia.of transmission line: 1.25mm2 or more
Refer to “Transmission Power Supply (30 V) Circuit Check Pro-
cedure.”
Replace outdoor unit circuit board or remote controller.
Items to be checked Measures to be taken
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