Fujitsu Mini-Split: 8 Flashes
A Fujitsu mini-split LED pattern starting with 8 flashes matches 4 documented codes: 82, 83, 84, 86. Watch the full pattern (short vs. long flashes) to tell them apart — all 4 are explained below.
Code 82: Sub-cool heat exchanger gas inlet or gas outlet thermistor error
Sub-cool heat exchanger gas inlet or gas outlet thermistor error. One of the sub-cooling heat exchanger gas sensors is shorted or open.
Manual wording: “Sub-Cool Heat Ex. Gas Inlet Thermistor Error / Sub Cool Heat Ex. Gas Outlet Thermistor Error - Sub cooling heat exchanger gas inlet temperature thermistor short or open detected.”
Documented for: RLF/RLF1 multi-zone systems on larger RLXFZ outdoor units
Likely causes, most common first
- Erroneous connection or removed connector
- Thermistor resistance out of specification
- Failed outdoor main PCB
What you can safely check yourself
- Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power
When to call a technician
Sub-cool circuit sensors are deep inside the outdoor unit. A technician must diagnose this.
A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 410A Mini-Split Troubleshooting Guide (Part # 6-26-FG2020 Rev. 5/2019) (Fujitsu General America, Inc., All R410A Halcyon mini-splits: RGLX, RL2/RLS3/RLS3H/RLS3Y/RLB/RLXB/RLXEH wall mounted, RLF/RLF1 multi-zone indoor units, RLXFZ multi-zone outdoor units, RML/RMLQ, RULX/RSLX universal-mount, RCLX cassettes) · checked 2026-08-25
Code 83: Liquid pipe thermistor error
Liquid pipe thermistor error. The heat exchanger liquid pipe sensor is shorted or open.
Manual wording: “Liquid Pipe Thermistor Error - Heat exchanger liquid pipe thermistor short or open detected.”
Documented for: RLF/RLF1 multi-zone systems on RLXFZ outdoor units
Likely causes, most common first
- Erroneous connection or removed connector
- Thermistor resistance out of specification
- Failed outdoor main PCB
What you can safely check yourself
- Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power
When to call a technician
The liquid pipe sensor is on refrigerant piping inside the outdoor unit. Have a technician replace it.
A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 410A Mini-Split Troubleshooting Guide (Part # 6-26-FG2020 Rev. 5/2019) (Fujitsu General America, Inc., All R410A Halcyon mini-splits: RGLX, RL2/RLS3/RLS3H/RLS3Y/RLB/RLXB/RLXEH wall mounted, RLF/RLF1 multi-zone indoor units, RLXFZ multi-zone outdoor units, RML/RMLQ, RULX/RSLX universal-mount, RCLX cassettes) · checked 2026-08-25
Code 84: Current sensor error
Current sensor error. The input current sensor read 0 amps while the inverter compressor was running above 56 rps, one minute after start-up (outside of defrost).
Manual wording: “Current Sensor Error - When input current sensor has detected 0A, while the inverter compressor is operating at higher than 56rps, after 1 minute upon starting the compressor.”
Documented for: RGLX, RL2/RLS3/RLB/RLXB, RLF/RLF1 outdoor units
Likely causes, most common first
- Loose terminal connection at the outdoor unit
- Connector removed from the current transformer
- Erroneous connection
- Failed current sensor or main PCB
What you can safely check yourself
- Turn the power off at the outdoor disconnect and breaker for about 5 minutes, then restore power
When to call a technician
The current sensor wraps the compressor supply conductor inside the electrical box. Only a licensed technician should open that.
A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 410A Mini-Split Troubleshooting Guide (Part # 6-26-FG2020 Rev. 5/2019) (Fujitsu General America, Inc., All R410A Halcyon mini-splits: RGLX, RL2/RLS3/RLS3H/RLS3Y/RLB/RLXB/RLXEH wall mounted, RLF/RLF1 multi-zone indoor units, RLXFZ multi-zone outdoor units, RML/RMLQ, RULX/RSLX universal-mount, RCLX cassettes) · checked 2026-08-25
Code 86: High pressure switch error, or on 42k and 48k units a pressure sensor error
High pressure switch error, or on 42k and 48k units a pressure sensor error. The high pressure switch was seen open for longer than 10 seconds after power was turned on.
Manual wording: “High Pressure Switch Error - When the pressure switch is detected open for longer than 10 seconds after the power is turned on.”
Documented for: 18/24/30/36 models show high pressure switch error; 42/48 models show pressure sensor error. RGLX, RLS3/RLB/RLXB, RLF/RLF1
Likely causes, most common first
- System high side pressure genuinely too high (blocked condenser airflow, dirty coil, overcharge)
- Failed or open high pressure switch
- Wiring or voltage fault at the pressure switch
What you can safely check yourself
- Clear leaves, snow, or debris away from the outdoor coil and fan so the unit can reject heat
- Make sure nothing is stacked on or against the outdoor unit
- Turn the power off at the disconnect for 3 to 5 minutes and back on
When to call a technician
Never jumper or bypass the high pressure switch - it is a safety device. Measuring switch voltage and resistance, or checking system pressures, requires a licensed technician with gauges.
A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 410A Mini-Split Troubleshooting Guide (Part # 6-26-FG2020 Rev. 5/2019) (Fujitsu General America, Inc., All R410A Halcyon mini-splits: RGLX, RL2/RLS3/RLS3H/RLS3Y/RLB/RLXB/RLXEH wall mounted, RLF/RLF1 multi-zone indoor units, RLXFZ multi-zone outdoor units, RML/RMLQ, RULX/RSLX universal-mount, RCLX cassettes) · checked 2026-08-25