Fujitsu Mini Split Error Code 22: Indoor Unit Capacity Error (Meaning, Causes, Fixes)

What the code means

Fujitsu's service manuals list E:22 as "Indoor unit capacity error". The ASU18RLF multi-zone service instructions describe it as the total capacity of the indoor units being installed beyond the allowed range, with the cause being an incorrect selection of indoor units or a failed outdoor unit main PCB. A wall-mount service manual in the same family describes detection as the total indoor capacity not matching the outdoor unit capacity within 3 minutes after power on. On units without a wired remote, the indoor unit shows it as 2 Operation light flashes and 2 Timer light flashes, with the Economy light flashing continuously. Fujitsu General America's support page adds the patterns for other series: 5 Operation and 7 Timer flashes on RMLQ/RML models, 22 or 1F on several wired remotes, and outdoor LED codes on some larger multi-zone outdoor units (for example E221 on the AOU48RLXFZ). Most importantly, Fujitsu notes that on multi-zone systems this code usually means the outdoor unit has lost communication with another indoor unit, and that other unit will often be flashing a communication error or show no lights at all.

Likely causes

• On a multi-zone system, one or more of the other indoor units isn't communicating with the outdoor unit (power off to that head, a loose or broken connecting wire, or a communication fault). Fujitsu says this is the usual reason.
• The indoor units connected to the outdoor unit add up to more or less capacity than the outdoor unit allows, which happens when the wrong combination was installed.
• Loose, broken or crossed field wiring between the outdoor unit and the indoor units.
• A failed outdoor unit main PCB, which Fujitsu's manuals list as the last cause once capacity and wiring check out.

Safe DIY checks

1. Write down which indoor unit shows 22 and look at every other indoor head on the same outdoor unit. Fujitsu says the head flashing 22 is the normal one; the problem is usually a head that's flashing a different code or is completely dark.
2. Check that every indoor unit has power. A tripped breaker, an off switch or a blown fuse on one head can leave the others showing a capacity error.
3. Turn the system off at the breaker for about 5 minutes and then back on, since this error is checked in the first few minutes after power-up.
4. If the system was just installed or an indoor unit was added or swapped, ask the installer to confirm the indoor models are an approved combination for that outdoor unit. Fujitsu publishes a multi-zone allowable combinations list.
5. If the code comes back with every head powered, call the installer or a licensed HVAC technician.

Parts that commonly fix it

Always match the part number to your exact model.

Related codes

• 35 Fujitsu Mini Split 35
• 53 Fujitsu Mini Split 53
• A1 Fujitsu Mini Split A1
• A3 Daikin Mini Split A3
• U0 Daikin Mini Split U0

All Fujitsu codes →

Sources

1. Fujitsu General America support, Indoor Capacity Error (blink patterns by model series, multi-zone communication checklist, allowable combinations list)
2. Fujitsu ASU18RLF (inverter multi) service instructions, Trouble shooting 5, E:22 Indoor Unit Capacity Error: incorrect indoor unit selection, replace outdoor main PCB, via ManualsLib
3. RSG18KMTE wall-mount service manual, 2-5 E:22 Indoor unit capacity error: total capacity doesn't match outdoor capacity within 3 minutes after power on, via ManualsLib
4. Fujitsu General Australia and New Zealand, Service Quick Reference ASTH18/22/24KMTD (E:22 Indoor unit capacity error, Operation 2, Timer 2, Economy continuous)