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Fujitsu / AIRSTAGE H-series

Fujitsu SW1 CODE DISPLAY status display

When the red ERROR LED is blinking, briefly pressing SW1 makes the MONITOR LEDs blink out the dot-decimal diagnostic code. The display method is not a separate failure.

Urgency
informational
Verified
Jul 30, 2026
Fix path
Not an error

What it means

When the red ERROR LED is blinking, briefly pressing SW1 makes the MONITOR LEDs blink out the dot-decimal diagnostic code. The display method is not a separate failure.

Urgency

Not an error

This is a normal status or service-mode indication, not an error, unless comfort is poor, the status never clears, or a separate SW1 fault code appears.

Likely causes

    Homeowner fix

    Record the exact dot-decimal code and which indoor position LED is lit, if visible. Do not remove covers or probe wiring to read more.

    When to call a pro

    Call a licensed HVAC technician if any fault code is shown. Give them the exact SW1/MONITOR code and the indoor unit letter if one was indicated.

    Repair vs replace

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

    Your Fujitsu model

    AIRSTAGE H-series model pages in the Fujitsu catalog help compare this repair path with current replacement options.

    Parts for this line

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

    Open parts page

    For your technician

    Technician note: Section 14-3 says to briefly push SW1 while the error is occurring; A/C/F/J/P/U map to 10/11/12/13/14/15 blinks. Page context: Fujitsu maps this display to the AIRSTAGE H-series line; source: Fujitsu AOUH18-45KWAS/KWAH R-32 Design & Technical Manual.

    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

    Record the exact dot-decimal code and which indoor position LED is lit, if visible. Do not remove covers or probe wiring to read more.

    Manual trigger

    When the red ERROR LED is blinking, briefly pressing SW1 makes the MONITOR LEDs blink out the dot-decimal diagnostic code. The display method is not a separate failure.

    Related codes

    Source

    Fujitsu AOUH18-45KWAS/KWAH R-32 Design & Technical Manual
    Section
    Section 14-3 Error code, Error code display
    Page
    PDF page 253; manual page 247

    Short quote: "briefly push the SW1"

    Sourced Jul 2026

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