F7,F8 And F9 Error Code marQ Air Conditioner

Error Code: F6/F7/F9 - External Temperature Sensor Fault All 3 error codes means there is something wrong with the sensors - the difference between the error codes are which type of sensor is coursing the problem. F6 means outdoor ambient air sensor fault F7 means outdoor coil sensor fault F9 means outdoor compressor sensor fault note: all 3 sensors are connected via the same plug so if one sensor is faulty then all the sensors need to be replaced. A multi-meter can be used to check for resistance, no resistance means faulty sensors. Check to see if the connection between the sensors and the PCB is firmly connected. Then check the sensor sockets are clean - as these are exposed to condensate water so they can corrode - use a small abrasive brush to clean the sockets. If the sensors are connected properly and the sockets are clean then the sensor set needs to be replaced.