Error A1 on Daikin FTXF35D Mini-Split | Causes & Fix

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• Source: Official Daikin service manual
• Reviewed by: Geo Technical Editorial
• Published: March 15, 2026
• Updated: March 15, 2026

Safety notice: Start with user-safe checks only. Do not open sealed refrigerant systems, inspect gas-train components, or work on energized high-voltage parts unless you are qualified to service this appliance.

Error A1 on Daikin : Indoor PCB fault. Follow the troubleshooting steps below to diagnose and fix this mini-split issue. ## What Error Code A1 Means on a Daikin FTXF35D Error A1 on the Daikin FTXF35D indicates a fault with the indoor unit PCB (Printed Circuit Board). Daikin uses the A1 code when the main control PCB has detected an internal self-diagnostic failure. This can be caused by a power surge, moisture ingress, or a component on the PCB failing (such as the EEPROM, microprocessor, or power supply circuit). A power cycle will often clear a transient A1, but a recurring A1 requires PCB replacement. When A1 appears, the Daikin mini split pauses normal operation to protect internal components from potential damage. Not every A1 fault requires a professional engineer — many are resolved through careful inspection and routine maintenance. Work through each diagnostic step below in sequence, starting with the simplest check, to identify the root cause efficiently before considering part replacement or arranging a service call. ## Symptoms - A1 flashing on indoor unit display

• Unit not responding to remote control
• System runs briefly then shuts down with A1 ## Common Causes - Indoor PCB fault ## Tools You May Need - Phillips screwdriver ## Step-by-Step Repair Guide | Step | Action | Result | |------|--------|--------| | 1 | Switch off the AC at the wall isolator or circuit breaker. Wait 5 minutes. | Power cycled — continue to step 2 if the issue persists. | | 2 | Restore power. If A1 clears and system operates normally, the fault was transient. | Fault transient or persists — continue to step 3 if the issue persists. | | 3 | If A1 recurs: isolate the unit and remove the indoor unit front panel. | Panel removed — continue to step 4 if the issue persists. | | 4 | Inspect the PCB for burn marks, moisture damage, or swollen capacitors. | PCB inspected — continue to step 5 if the issue persists. | | 5 | Replace the indoor PCB if visible damage found or if A1 is recurring after power cycle. | PCB replaced — if the fault remains, contact a qualified technician. | ## Safety Precautions Isolate the AC at the circuit breaker before accessing the indoor unit PCB. The PCB operates at mains voltage — do not touch components with the unit powered. ## Estimated Repair Time and Difficulty Most mini split error code A1 faults can be assessed and addressed in 30–90 minutes using the steps above. The diagnostic process requires only basic tools: a multimeter and standard screwdrivers cover the majority of checks described here. If a replacement part is required, allow 1–5 working days for delivery. A trained technician with access to the correct diagnostic equipment will typically resolve this type of fault within a single service visit. ## When to Call a Technician Contact a Daikin authorised service technician if: the fault persists after following all the steps above; if PCB-level or refrigerant-circuit work is required; or if you are not comfortable working with electrical or mechanical components. When calling, have the full model number, the error code displayed, and a brief description of any sounds or symptoms you noticed before the fault appeared — this helps the technician prepare the correct parts and tools. ## Frequently Asked Questions Q: Will A1 appear after a power cut? Yes — power surges or interruptions during operation can corrupt PCB firmware or cause a transient fault that clears with a power cycle. Q: Can I replace the Daikin indoor PCB myself? PCB replacement requires matching the exact part number and correct firmware. Daikin recommends authorised engineer installation for PCB replacement. Q: Is A1 covered by Daikin warranty? PCB faults within the warranty period are covered. Provide the unit serial number and installation date when contacting Daikin. ### Is it safe to keep using my Daikin with error A1? If error A1 does not indicate an immediate safety hazard such as a gas leak, electrical short, or water flooding, you can continue limited use while monitoring the appliance. However, running the mini-split with an active error code increases the risk of further damage. Address the underlying issue as soon as possible. For high-severity errors, disconnect the appliance and contact a qualified technician. ### How much does it cost to fix error A1 on a Daikin ? Repair costs for error A1 on the Daikin mini-split depend on the root cause. DIY fixes such as cleaning filters, resetting the unit, or reconnecting loose wires cost nothing beyond basic tools. If a component replacement is needed, parts and labor from a certified technician are the main expenses. Contact a Daikin-authorized service provider for an accurate estimate based on your specific situation. ### What does error code A1 mean on a Daikin mini-split? Error code A1 on Daikin mini-split models indicates Indoor PCB fault. This error is detected by the appliance’s internal diagnostic system and displayed to alert the user that attention is needed. Refer to the troubleshooting steps above for guidance on resolving this issue. ### Is it safe to keep using my Daikin with error A1? If error A1 does not indicate an immediate safety hazard such as a gas leak, electrical short, or water flooding, you can continue limited use while monitoring the appliance. However, running the mini-split with an active error code increases the risk of further damage. Address the underlying issue as soon as possible. For high-severity errors, disconnect the appliance and contact a qualified technician. ### How much does it cost to fix error A1 on a Daikin ? Repair costs for error A1 on the Daikin mini-split depend on the root cause. DIY fixes such as cleaning filters, resetting the unit, or reconnecting loose wires cost nothing beyond basic tools. If a component replacement is needed, parts and labor from a certified technician are the main expenses. Contact a Daikin-authorized service provider for an accurate estimate based on your specific situation. ### What does error code A1 mean on a Daikin mini-split? Error code A1 on Daikin mini-split models indicates Indoor PCB fault. This error is detected by the appliance’s internal diagnostic system and displayed to alert the user that attention is needed. Refer to the troubleshooting steps above for guidance on resolving this issue.