October 28, 2025 - The Daikin U9 error code basically means a transmission defect, a communication problem between the indoor unit and the outdoor unit. The U9 error can be caused by a faulty evaporator coil, indoor thermistor, and indoor PCB.

Error U9 typically indicates a communication fault between the master controller and thermostat. Start by resetting the system using the Cancel button for 10 seconds. Check wiring connections at the thermostat and control board for loose or ...

Transmission error between main and sub remote · controller · Connection between sub remote controllers · Defective remote controller PCB · k k k k k k · U9 · Malfunction of transmission (other · system) Transmission error between other indoor and outdoor units ·

Daikin air conditioner error code U9: Signal transmission error between indoor unit and outdoor unit in the same system.. Diagnose the root cause with service manual references.

Main/sub switch not set, wiring error, defect of remote controller · • · • · • · • · U9 · System communication failed · Fault with other indoor unit, no power, A9 · • · UA · Improper combination · Incorrect field setting, wiring, defect of PCB ·

March 15, 2024 - A9 Is an indoor EEV coil failure. You can confirm this by checking what units are producing a u9 error code and which us giving a different error code thats on tbe same branch. Daikins will typically throw a u4-01 or like this case U9 on all the units expect the one with the issue.

August 10, 2012 - Re: Daikin air conditioner flashing fault code u9 · U9 System communication failed Fault with other indoor unit, ie no power, Faulty PCB · Helpful 0 · Not Helpful · Add a Comment · You can't post conmments that contain an email address.

Transmission error between other indoor and outdoor units Defective electronic expansion valve of other indoor unit Defective indoor unit PCB of other indoor unit Improper connection of transmission wiring between indoor and outdoor unit

Error codes U3 (outdoor) and U4, U5, U9 (indoor) on the Daikin RXYQ120TATJU indicate communication or sensor faults. First, power off and check all wiring connections between indoor and outdoor units for looseness or damage.

Error Code Search offers information on the cause of the malfunction and the status of your air conditioner by entering the error code. Error Code Search List of Error Codes(0.1MB) Please refer to "How to Check Error Codes" for step-by-step instruction to check the error codes.

November 4, 2014 - Daikin RQYQ140-180PY1 Manual Online: U9 '' Indoor Unit: Malfunction Of Transmission Between Indoor And Outdoor Units In The Same System. U9 Remote Controller Display Applicable All indoor unit models Models RQYQ-PY1 RQEQ-PY1 Method of Detect ...

July 20, 2025 - Easily identify Daikin HVAC system faults with this complete list for simple self-diagnosis & troubleshooting. Includes VRV, SkyAir, HRV systems, and more.

April 20, 2026 - Being one of the most well-known Aircon Brands, Daikin has an advanced error code detection system. Unlike other common brands, the number of times the aircon timer light blinked does not reflects the error itself. Instead, whenever the Aircon TIMER LED started blinking, you will need to press the Cancel Button on your remote control.

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December 22, 2022 - U0 System Shortage of refrigerant ... units U8 System Transmission between master and slave RC U9 System Transmission error between indoor to outdoor UA System Excessive number of fancoils UC System Address duplication of central ...

November 10, 2025 - Note this code and reset your system by switching off the mains power and leaving it for 20 – 30 minutes. This reset may be all you need to fix the issue; however, if the system malfunctions again or doesn’t work after the reset, contact Peninsula Air Conditioning. ... Hi there 👋 Need help with your air conditioner? We primarily support Daikin products, but can do others too I can guide you through: • Error codes (e.g.

March 11, 2024 - A complete Daikin step-by-step guide to troubleshooting, error codes and what they mean, model numbers, and more!