The most common cause is a problem with the water removal system. This often triggers a "float switch" safety shutoff.
If the copper pipes connecting the indoor and outdoor units are crushed, kinked, or blocked (by debris or ice), the refrigerant cannot circulate properly, leading to a pressure build-up on the discharge side.
continues to flash after a reset, it likely signifies a hardware failure in the indoor PCB fan motor controller o general ac error code 9c
. This typically occurs when the unit detects unstable incoming electricity, such as a significant drop in voltage (undervoltage) or a sudden surge 1. Identify the Cause
To help me give you a more precise answer, could you tell me: Is your AC a Split, Cassette, or Window Fixed Speed (Non-Inverter) model? Does the unit start for a few minutes before the error appears, or does it show up immediately O General AC Error Codes Guide – Troubleshooting & Fixes The most common cause is a problem with
| Solution | Action Required | Success Rate | |----------|----------------|---------------| | | Unplug for 15–30 mins to clear volatile memory. | Low (temporary) | | Replace Indoor PCB | Order O General original spare indoor main board. | High | | Replace Outdoor PCB | For split units if communication originates there. | High | | Reprogram EEPROM | Requires specialized programmer; not recommended for field service. | Medium | | Jumper Adjustment | If model incorrectly set (e.g., 9c shown after board replacement). | Medium |
Keep one probe of your multimeter securely pressed against an unpainted copper pipe of the AC chassis. continues to flash after a reset, it likely
To fix the error, you must identify the root cause. Here are the seven most common reasons for the 9C fault:
: Sometimes, a simple reset can resolve the issue. This can usually be done by turning off the AC at the mains, waiting for a few minutes, and then turning it back on. However, be cautious with resets as they might not address underlying problems.
If you suspect a refrigerant leak or overcharging, contact a professional HVAC technician for assistance.
A qualified technician will check the indoor PCB to ensure the EEPROM chip is firmly seated in its socket. 2. Replacing the PCB/EEPROM