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2WAY VRF SYSTEM
Trouble Diagnosis
3. 2WAY Alarm Codes
E20 Alarm (U-72ME2U94 / U-96ME2U94 / U-120ME2U94 / U-144ME2U94)
Alarm code
E20
Alarm meaning
No indoor unit responded in Auto Addressing.
Alarm conditions
When auto address setting was performed, no indoor units were recognized.
Probable cause
(1) The inter-unit control wiring from the outdoor unit to the indoor units has been cut.
(2) Serial wire is disconnected at the outdoor unit.
(3) The power is OFF at all indoor units in the system.
Check
(1) Check whether the inter-unit control wiring from the outdoor unit to the indoor units is cut.
(2) Check whether serial wire is disconnected at the terminal TM1(1,2).
(3) Check the power at the indoor units.
Correction
(1) Reconnect the inter-unit control wire from the outdoor unit to the indoor unit.
Example
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Notes
Position of serial terminal TM1 (1, 2) on 2WAY
terminal TM1 (1, 2)
E24 Alarm
Alarm code
E24
Alarm meaning
No response from sub outdoor unit.
Alarm conditions
After initial communications were completed, communications from an outdoor unit stopped.
Probable cause
(1) After initial communications were completed, the control wiring between main and sub
outdoor units was disconnected.
(2) After initial communications were completed, the outdoor unit power was turned OFF.
Check
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Correction
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Example
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Notes
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SM830237-07_北米向け2WAY_VRF.indb 9
18/06/18 18:50:10