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Daikin · Heat Pump

Daikin VRV IV RXTQ-TA / RXTQ-TB error codes

Daikin VRV IV RXTQ heat pump codes. 59 codes.

Check this is your model before you read on

Check the model number on the data plate before trusting any code on this page. These are letter and number pairs rather than counts, so there is no counting step. The letter group is the important part, because it identifies the unit reporting the code. The indoor group is A and C, the outdoor group is E, F, H, J, L and P, and the system group is U and M. M codes belong to the centralized controller rather than to any unit, and the rest of the M group is a controller network problem rather than a refrigerant or mechanical fault. Some indoor codes carry a sub-code with a dash, such as A6-01 or A9-02, and the sub-code narrows the fault to a specific cause within the parent code.

The RXTQ outdoor unit serves VRV indoor units over a shared communication bus, and the factory splits the code list by which unit reports it. A and C codes come from indoor units, E, F, H, J, L and P from the outdoor unit, and U and M are system or centralized controller faults. This is a commercial and light commercial multi split platform, not a residential one indoor mini split unit.

How to read this code

First decide which unit the code came from, because Daikin splits the list three ways and the letter tells you. A and C codes are reported by the indoor unit, E, F, H, J, L and P codes are reported by the outdoor unit, and U and M codes are system level faults that belong to no single unit. On a VRV system one outdoor unit serves many indoor units, so a C code on the wall controller is an indoor unit fault and a C code on the outdoor unit is something else entirely. A and C codes are the indoor group, E, F, H, J, L and P are the outdoor group, and U and M are the system group. The outdoor unit is the RXTQ heat pump and the indoor units are the VRV indoor units on the same bus. Some codes are warnings rather than stops: the operation lamp stays lit instead of blinking, the system keeps running, and the manual still asks for the condition to be checked. A7, AF, CC, CE, P4, UC and U0 are in that group, and CJ is the odd one out because the manual says it may or may not keep running depending on conditions. U0 is the warning worth treating as an emergency, because a system short of refrigerant destroys its compressor while it keeps running.

59 codes on this control platform.

59 fault codes

Every one of these means something is wrong. Ordered by how urgent they are.

A0DaikinIndoor unit external protection device abnormalityA1DaikinIndoor unit control board abnormalityA3DaikinDrain level control system abnormalityA6DaikinIndoor fan motor lock or overloadA7DaikinSwing flap motor abnormality, warningA8DaikinIndoor unit power supply voltage abnormalityA9DaikinIndoor unit electronic expansion valve abnormalityAFDaikinDrain water level above the limit, warningAHDaikinSelf cleaning decoration panel abnormalityAJDaikinCapacity setting errorC1DaikinTransmission abnormality between the indoor and fan boardsC4DaikinIndoor heat exchanger liquid pipe thermistor abnormalityC5DaikinIndoor heat exchanger gas pipe thermistor abnormalityC6DaikinIndoor unit and fan board combination errorC9DaikinSuction air thermistor abnormalityCADaikinDischarge air thermistor abnormalityCCDaikinHumidity sensor system abnormality, warningCEDaikinInfrared presence or floor sensor error, warningCJDaikinRemote controller thermistor abnormality, warningE1DaikinOutdoor unit main board abnormalityE3DaikinHigh pressure switch activationE4DaikinLow pressure protection activationE5DaikinCompressor motor lockE7DaikinOutdoor fan motor abnormalityE9DaikinOutdoor electronic expansion valve abnormalityF3DaikinDischarge pipe temperature abnormalityF6DaikinRefrigerant overchargeH9DaikinOutdoor air thermistor abnormality, R1TJ3DaikinDischarge pipe thermistor abnormality, R2TJ5DaikinSuction pipe thermistor abnormality, R3T and R5TJ6DaikinOutdoor heat exchanger deicer thermistor abnormality, R4TJ7DaikinOutdoor heat exchanger liquid pipe thermistor abnormality, R7TJ9DaikinSubcooling heat exchanger gas pipe thermistor abnormality, R6TJADaikinHigh pressure sensor abnormalityJCDaikinLow pressure sensor abnormalityL1DaikinInverter board abnormalityL4DaikinRadiation fin temperature rise abnormalityL5DaikinCompressor instantaneous overcurrentL8DaikinCompressor overcurrentL9DaikinCompressor startup abnormalityLCDaikinTransmission error between the outdoor board microcomputersM1DaikinCentralized controller board defectM8DaikinTransmission error between centralized controllersMADaikinPoor centralized controller combinationMCDaikinAddress duplication and poor setting, warningP1DaikinInverter circuit capacitor high voltageP4DaikinRadiation fin thermistor abnormality, warningU0DaikinRefrigerant shortage, warning that should not be ignoredU2DaikinPower supply insufficient or instantaneous abnormalityU3DaikinCheck operation not executedU4DaikinTransmission error between indoor and outdoor unitsU5DaikinTransmission error between the controller and the indoor unitU8DaikinTransmission error between main and sub controllersU9DaikinTransmission error within the same systemUADaikinImproper indoor and outdoor unit combinationUCDaikinCentralized controller address duplication, warningUEDaikinTransmission error between the centralized controller and an indoor unitUFDaikinSystem not set yetUHDaikinSystem address undefined