Fujitsu · Heat pump

51 Indoor fan motor error

High 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

Indoor fan is turning far slower than commanded (UK data: below 1/3 of target for over 56 s) or is locked. Indoor lamps: OPERATION (green) flashes 5x, TIMER (orange) flashes 1x, ECONOMY (green) flashes fast nonstop; wired remote shows 51.

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

Fan wheel jammed or bearing seized
Motor winding open
Motor overheated by nearby heat source
Indoor fan motor failure
Main PCB failure

Test and repair steps

With power off, spin the fan by hand - it should turn freely; fix a loose, rubbing or seized wheel/bearing.
Check for anything heating the motor area; let it cool and retry.
Test the indoor fan motor per the service parts check; replace if bad.
If the motor checks good, replace the indoor main PCB.

Settings for these units

Operating range and service space · Fujitsu multi-zone outdoor 18/24 type

Other codes on the same units

39 Indoor fan motor power supply error
41 Room (intake air) temperature sensor error
42 Indoor coil (heat exchanger middle) sensor error
44 Human (occupancy) sensor error
52 Indoor electronic expansion valve error
53 Drain pump error
57 Damper error
58 Intake grille error

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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.