Haier AW07LC2VHA Technical Overview page 31

OUTDOOR UNIT ERROR CODES
Indoor Unit and Outdoor Unit Communication Errors
Error Code 15
This error indicates the indoor unit and outdoor unit are having a problem communicating information. The wiring path for
the data signal is between Terminals 3 to 1 on the Terminal Blocks connecting the indoor unit to the outdoor unit. If the path
is correct, the GREEN LED on the Service Monitor Board should be lit. Check the wiring on ECU Plug CN-21 to the individual
Indoor Unit Terminal Blocks to ensure there are no loose connections. If OK, make sure the wiring size between indoor and
outdoor units is 14 gauge AWG Stranded Wire. Check that no twists in the wires/wire nuts are present in the wires between
indoor unit and outdoor unit Terminals 1 and also 3. (These are data path wires.) Reference Section Service Monitor Board
Test.
Error Codes Caused by Abnormal Refrigeration Circuit Conditions
Error Code 8
This code indicates the temperature of the compressor hot gas is too high. This error would have occurred despite the ECU
attempt at reducing operating frequency. Causes of this type of condition are typically a lack of refrigerant in the system,
excessive heat in the conditioned space or a restriction in the refrigeration circuit.
Error Code 16
This error code indicates the system may lack refrigerant. Recover the system charge and check charge level.
Error Code 21
This code indicates the indoor coil has frosted over. Typically this condition will be due to a lack of heat in the conditioned
space, operating the indoor unit at excessively cold air temperature or a blockage of air flow to the indoor unit. (Failed indoor
fan motor.) This condition will cause the system to try and enter an anti freezing cycle. Refer to the Temperature Sensor
Response section for details.
Outdoor Error Code Related to INDOOR UNIT Operation
Error Code 21
This code indicates the indoor coil sensor has detected a coil temperature that is too cold. Refer to Temperature Sensor
Responses for diagnostic details. Likely causes are a lack of heat in the space. (Frost is a normal condition.)
Error Code Related to the ECU Board Operation
Error Code 1
The ECU board CPU can not read or write data. Replace the ECU Board.
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ERROR CODES