Fujitsu DEFROST DURING CHECK RUN status display

What it means

During check-run result display, the manual says automatic defrost may operate if frost is on the outdoor unit. That is a normal protective operation, not an error by itself.

Urgency

Likely causes

1. Temporary protection event that may clear after one reset
2. Airflow, power, or operating condition outside normal range
3. Sensor, wiring, or control feedback problem
4. Technician-only component fault identified by the service manual

Homeowner fix

Let defrost finish. Keep snow and loose debris away from the outdoor unit base, but do not chip ice from the coil.

When to call a pro

Call for service if the outdoor unit remains encased in ice, heating does not resume, or a separate SW1 fault code appears.

Repair vs replace

This is a status display, not a repair-or-replace decision.

• Fujitsu AIRSTAGE H-series Compact Cassette 9,000 BTU R-32 208/230V (ACUH09KUAS / AOUH09KUAS1)

  AIRSTAGE H-series

• Fujitsu AIRSTAGE H-series Compact Cassette 12,000 BTU R-32 208/230V (ACUH12KUAS / AOUH12KUBS1)

  AIRSTAGE H-series

• Fujitsu AIRSTAGE H-series Floor-Mounted Console 12,000 BTU R-32 208/230V (AGUH12KUAS / AOUH12KUBS1)

  AIRSTAGE H-series

• Fujitsu AIRSTAGE H-series Mid Static Duct 12,000 BTU R-32 208/230V (ARUH12KUAS / AOUH12KUBS1)

  AIRSTAGE H-series

Parts for this line

The parts catalog for Fujitsu AIRSTAGE H-series lists 6 sourced replacement parts for this product line.

For your technician

Technician note: Section 14-1 says to proceed after automatic defrost finishes during displayed check-run results. Page context: Fujitsu maps this display to the AIRSTAGE H-series line; source: Fujitsu AOUH18-45KWAS/KWAH R-32 Design & Technical Manual; display convention: match the letter D, letter E, letter F, letter R, letter O, letter S, letter T, letter D, letter U, letter R, letter I, letter N, letter G, letter C, letter H, letter E, letter C, letter K, letter R, letter U, and letter N marker exactly before comparing neighboring codes.

Which systems show it

• Fujitsu Halcyon/AIRSTAGE R-32 AOUH18KWAS2, AOUH24KWAS3, AOUH36KWAS4, and AOUH45KWAS5 outdoor-unit manuals where Section 14-3 lists the same SW1/MONITOR error-code table.
• Fujitsu AOUH18KWAH2 and AOUH36KWAH4 XLTH sibling design manuals where the extracted Section 14-3 table matches the KWAS manuals.

Related troubleshooting

Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.

Reset note

Let defrost finish. Keep snow and loose debris away from the outdoor unit base, but do not chip ice from the coil.

Manual trigger

During check-run result display, the manual says automatic defrost may operate if frost is on the outdoor unit. That is a normal protective operation, not an error by itself.

Related codes

Source

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