Panasonic U-8MF2E8 Service Manual page 131

4. 3WAY Alarm Codes
E16 Alarm
Alarm code E16
Alarm meaning Automatic address setting alarm (too many units)
Alarm conditions • The number of indoor units was too many when automatic address setting was performed.
• After initial communications were completed, an unrecognized unit was detected.
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 (1) Refer to the test run servicing materials and check the number of indoor units that is set.
(2) Check the inter-unit control wiring at the indoor and outdoor units.
Correction After correcting the indoor unit quantity setting or the inter-unit control wiring, perform automatic
address setting again.
Example —
Notes —
E20 Alarm
Alarm code E20
Alarm meaning No indoor units at automatic address setting.
Alarm conditions When automatic 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 connector 1 (CN76) 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 connector 1 (CN76) is disconnected at the outdoor unit.
(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 —
Notes Position of serial connector CN76 on 3WAY
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 —
Correction —
Example —
Notes —
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3WAY SYSTEM
Trouble Diagnosis
OC
CN76
5