Fujitsu air conditioner 11 error code: indoor and outdoor units not communicating
Also shown as E11
- Urgency
- Medium
- Who can fix it
- Moderate DIY
- Time
- About 20 min
- Repair cost
- $150–$600
What the 11 code means
Error 11 on a Fujitsu mini-split is a serial communication error: the indoor and outdoor units are not talking. On a unit without a wired remote, the operation lamp blinks once, the timer lamp blinks once and the economy lamp flashes continuously.
The indoor and outdoor units swap a serial signal over the connecting cable. Fujitsu's service manuals say the indoor unit flags this error when it cannot receive the signal from the outdoor unit for more than 2 minutes after power-on, or for more than 15 seconds during normal running.
You will usually see the unit stop heating or cooling. On older service manuals the code is written E:11, so you may see it called E11.
Common causes
Listed from most to least common.
- Breaker or disconnect for the outdoor unit off or tripped
- Loose, damaged or wrongly connected wiring between the panel, outdoor unit and indoor unit
- Wire nuts or splices in the connecting cable
- Low or unstable supply voltage
- Indoor or outdoor control board fault
How to fix the 11 code
Unplug the air conditioner or switch it off at the breaker before removing any panel or filter.
Step 1: Check the outdoor unit has power
Look at the breaker panel and the disconnect box next to the outdoor unit. If the outdoor unit is off, the indoor unit cannot hear from it.
Step 2: Reset the power
Switch off the breaker for the system for at least 5 minutes, then switch it back on. Fujitsu's first check for this code is to reset the power and run the unit again.
Step 3: Look at the outside cable
Without opening any panels, follow the cable from the wall to the outdoor unit. Look for crushed or chewed insulation or a missing cover.
Step 4: Call the installer for new systems
If error 11 started right after installation, tell the installer. Fujitsu's troubleshooting guide says wire nuts and splices in the connecting cable are not recommended.
You'll need: Flashlight.
How to read Fujitsu blink codes
With a wired remote, the code shows on the remote's screen. With the handheld remote only, the indoor unit shows the code with its lamps. Count the flashes of the operation lamp (green) and then the timer lamp (orange). The economy lamp flashes continuously to tell you this is an error code.
The operation count is the first digit and the timer count is the second. So 1 and 1 is code 11, and 6 and 2 is code 62. Ten operation flashes stand for the letter A, so 10 and 1 is code A1. Count at least two full cycles before you call, and give the technician the code and your model number.
How to reset the Fujitsu air conditioner
- Turn the system off with the remote or wired controller.
- Switch off the breaker for the system, and the outdoor disconnect switch if there is one. Leave the power off for at least 5 minutes.
- Restore power and turn the unit back on. The compressor normally waits a few minutes before starting, so give it time before judging.
- If the same code or blink pattern comes back, the fault is still there. Work through the fix steps above, or call a Fujitsu contractor or other licensed HVAC technician.
When to call a technician
If error 11 returns after a reset, call a licensed HVAC technician. Fujitsu's diagnosis means checking the wiring and voltages at the panel, the outdoor unit and the indoor unit with the power on.
A typical repair for this code costs $150–$600 in the US, including parts and labor. Prices vary by area and model.
Models this applies to
- Halcyon wall-mounted mini-splits (ASU indoor, AOU outdoor)
- Halcyon floor, ceiling cassette and slim duct units (AGU, AUU, ARU)
- Halcyon multi-zone systems (RLF series)
- Ducted and ceiling-suspended units (RGLX, RULX series)
Codes can differ slightly between models. Your owner's manual is the final word and is available from Fujitsu support.
Frequently asked questions
›How do I read error 11 without a wired remote?
Count the blinks. For error 11, the green operation lamp blinks once and the timer lamp blinks once, while the economy lamp flashes continuously. The number of operation blinks is the first digit and the number of timer blinks is the second.
›Can a power outage cause error 11?
Yes. A brief outage or surge can leave the units out of step. Turn the breaker off for 5 minutes and back on. If 11 does not return, nothing else is needed.
›Why are my Fujitsu lamps blinking but there is no error?
Fujitsu says the operation and timer lamps blink alternately after the power was cut during operation, such as in an outage, and blink together during a test run. Neither is a fault.