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Fujitsu · Heat pump

12 Wired remote controller communication error

Medium severity Fujitsu ductless split/multi/VRF (general code list)Fujitsu wall-mounted 7-15 (NA ASU/AOU type)Fujitsu slim duct ARU 7-18 (LL type)

What the control is telling you

The indoor unit has lost the wired remote signal for over a minute. Indoor lamps: OPERATION (green) flashes 1x, TIMER (orange) flashes 2x, ECONOMY (green) flashes fast nonstop; wired remote shows 12.

Applies to: Fujitsu ductless heat pumps: Fujitsu ductless split/multi/VRF (general code list), Fujitsu wall-mounted 7-15 (NA ASU/AOU type), Fujitsu slim duct ARU 7-18 (LL type)

Likely causes

  • Remote cable loose, broken or wrong
  • Remote type does not match the 2-wire / 3-wire DIP setting (ducted units)
  • Faulty remote
  • Indoor main PCB fault

Test and repair steps

  1. Power off and check the remote cable at both ends for loose or broken conductors.
  2. On ducted units make sure the board DIP switch matches the remote type (2 WIRE factory, 3 WIRE for 3-wire remotes).
  3. Measure the remote supply at the communication kit connector (UK data: CN300 pins 1-3): about DC 12 V means the board is fine and the remote is bad; 0 V means the indoor PCB is bad.
  4. Replace the faulty part and cycle power.

Settings for these units

Other codes on the same units

  • 6A Display PCB micro communication error
  • 9A Expansion valve coil error
  • 9U Outdoor unit error (general)
  • 11 Serial communication error (indoor/outdoor)
  • 14 Network communication error
  • 15 Check run unfinished / airflow auto-adjust error
  • 16 Peripheral unit / transmission PCB connection error
  • 18 External communication error (WLAN / option adapter)

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Source: Fujitsu All Fujitsu split - multi - VRF (generic code list) codes.pdf - section error code table (indoor LED flashes); Fujitsu Wall-mounted 7-9-12-15 (North American trilingual, UTY-RNNUM remotes; e.g. ASU9-12-15 RLF1-RLS familie.pdf - section 14 Error codes; Fujitsu Wall-mounted KMCG (ASEH-AOEH 07-14) - Fujitsu UK; same error-code scheme as NA ASU-AOU units service S.pdf - section 3 Troubleshooting, 2 Troubleshooting with error code; Fujitsu Slim duct AR07-09-12-14-18 (ARU-ARYG LL-type equivalent) installation P-N 9381858064.pdf - section 14 Error codes. Summarized in our own words; check the original manual for your model.

Homeowner looking at this code? See what it means for you and when to call a technician.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.