HVACopediaFujitsu · Heat pump
Outdoor LED1 12 flashes Overcurrent trip detection (outdoor board LED)
What the control is telling you
Multi-zone 18/24 outdoor board: LED1 flashes 12 times while the other LEDs stay off. Same fault family as indoor code 94. The LEDs sit on the back side of the board and are seen through a hole.
Applies to: Fujitsu 18 type (2-zone) and 24 type (3-zone) multi outdoor units
Likely causes
- Compressor overloaded or locked
- Blocked outdoor coil / fan fault
- Overcharge or restriction
- PCB fault
Test and repair steps
- Look at the outdoor PCB LEDs (rear of the board, viewed through the hole) and count the flashes on each LED.
- Then follow the checks for indoor code 94: Check outdoor airflow, coil and fan.
- Check refrigerant charge and for restrictions.
- Check compressor windings and current.
Settings for these units
Operating range and service space · Fujitsu multi-zone outdoor 18/24 type
| Item | Value |
|---|---|
| Cooling outdoor range | 14 to 115 F DB |
| Heating outdoor range | 5 to 75 F DB |
| Cooling indoor range | 65 to 90 F DB |
| Heating indoor range | 60 to 88 F DB |
| Rear (open top, rear wall only) | 4 in. or more |
| Rear + sides | 4 in. rear, 10 in. sides |
| Front wall only | 24 in. or more |
| Between side-by-side units | 10 in. or more |
| Base height | 2 in. or more above floor |
Unit tilt no more than 3 degrees and never toward the compressor side.
Below 32 F outdoor do not fit the drain pipe/caps (freezing).
Other codes on the same units
- Outdoor LED1 1 flash Serial comms error, outdoor to indoor unit A (outdoor board LED)
- Outdoor LED1 10 flashes High pressure switch 2 error (outdoor board LED)
- Outdoor LED1 11 flashes Indoor unit capacity error (outdoor board LED)
- Outdoor LED1 13 flashes Compressor rotor position detection error (outdoor board LED)
- Outdoor LED1 14 flashes Trip terminal L error (outdoor board LED)
- Outdoor LED1 15 flashes Outdoor fan motor error (outdoor board LED)
- Outdoor LED1 17 flashes Outdoor PCB micro communication error (outdoor board LED)
- Outdoor LED1 18 flashes High discharge temperature (outdoor board LED)
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Source: Fujitsu Outdoor unit 18-24 type (North American trilingual) installation P-N 9374747160.pdf - section 8.2 Outdoor unit LED. Summarized in our own words; check the original manual for your model.
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