Error, fault and alarm codes of products - what each code means, its causes and what to do - read from the manufacturers’ manuals, with the manual page each answer comes from.
12.1 on the Fujitsu General 410A is listed in the manual as: Indoor unit main PCB error. The manual lists no action for this code.
The system detected an external communication error. The manual lists no action for this code.
Remote controller communication error The manual lists no action for this code.
Serial communication error between indoor/outdoor units The manual lists no action for this code.
Outdoor unit discharge temperature 1 error The manual lists no action for this code.
The outdoor unit 4-way valve has an error. The manual lists no action for this code.
Outdoor unit fan motor 1 error The manual lists no action for this code.
Outdoor unit compressor motor control error The manual lists no action for this code.
Outdoor current sensor error The manual lists no action for this code.
Outdoor air temp. thermistor error code 74.1 indicates a problem with the outdoor temperature sensor. The manual lists no action for this code.
Outdoor unit heat exchanger temperature thermistor error The manual lists no action for this code.
Outdoor unit discharge temp. thermistor error The manual lists no action for this code.
Outdoor unit discharge temp. thermistor error The manual lists no action for this code.
The outdoor unit IPM error has occurred. The manual lists no action for this code.
The outdoor unit has a filter or PFC circuit error. The manual lists no action for this code.