Panasonic U-8MF2E8 - Page 131

5
5 - 9
3WAY SYSTEM
Trouble Diagnosis
4. 3WAY Alarm Codes
E24 Alarm
Alarm code E24
Alarm meaning Outdoor unit failed to receive communication from other 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 cut.
(2) After initial communications were completed, the outdoor unit power was turned OFF.
Check —
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Correction
Example
Notes
E16 Alarm
Alarm code
Alarm meaning
Alarm conditions
After initial communications were completed, an unrecognized unit was detected.
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Probable cause (1) The number of indoor units set at the indoor unit quantity setting SW (SW3, SW4) on the
outdoor unit PCB is less than the number set.
(2) The inter-unit control wiring is wired incorrectly.
Check
(2) Check the inter-unit control wiring at the indoor and outdoor units.
Correction
address setting again.
Example
Notes
E16
Automatic address setting alarm (too many units)
The number of indoor units was too many when automatic address setting was performed.
(1) Refer to the test run servicing materials and check the number of indoor units that is set.
After correcting the indoor unit quantity setting or the inter-unit control wiring, perform automatic
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E20 Alarm
Alarm code
Alarm meaning
Alarm conditions
Probable cause
(2) Serial connector 1 (CN76) is disconnected at the outdoor unit.
(3) The power is OFF at all indoor units in the system.
Check
(2) Check whether serial connector 1 (CN76) is disconnected at the outdoor unit.
(3) Check the power at the indoor units.
Correction
Example
Notes
E20
No indoor units at automatic address setting.
When automatic address setting was performed, no indoor units were recognized.
(1) The inter-unit control wiring from the outdoor unit to the indoor units has been cut.
(1) Check whether the inter-unit control wiring from the outdoor unit to the indoor units is cut.
(1) Reconnect the inter-unit control wire from the outdoor unit to the indoor unit.
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Position of serial connector CN76 on 3WAY
OC
CN76
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