98
Failure code
Outdoor 
digital 
display tube: 
26-0, 1, 2
Indoor wired 
controller: 
1A
Indoor unit LED status
LED5F ailure description: 
Communication between indoor unit and 
outdoor unit failure
20 times
Outdoor unit LED status
LED1 LED2
Normal Normal
1. Model Failure diagnosis and troubleshooting
MRV 5-HR series 
DiagnosisT roubleshooting
2. Abnormity detection method
◆
Grounded short-circuit 
of communication wire, or 
disconnected communication 
wire P and Q;
◆
Incorrect wiring of 
communication wire P and Q;
◆
Uniform indoor unit power 
supply, and partial indoor unit 
being powered off.
◆
Larger interference and 
unstable communication signal.
◆
Failure in PCB of indoor and 
outdoor unit results in unstable 
communication.
conditions
It is not detected that there 
is indoor unit connection for 
200 rounds continuously; it 
is detected that the number 
of indoor units is less than 
set number for 270 seconds 
continuously; it is detected that 
the number of indoor units is 
more than set number for 170 
seconds continuously.
4. Possible causes
◆Poor communication wire: 
short circuit and disconnection;
◆Incorrect wiring of 
communication wire P and Q P 
and Q;
◆Poor PCB results poor 
communication;
◆Larger interference of normal 
communication.
Replace i t  correctly by after-
sales personnel on site.
Check  i f  the  communication  
wire of outdoor unit is shorted
Check if the communication wire 
of outdoor unit is disconnected
Check if the communication 
wire P and Q of indoor and 
outdoor unit is incorrect
Check if there is same indoor unit No.
Replace indoor or outdoor computer board
Check if the computer board 
communication port of indoor 
and outdoor unit is correct
Check if there is interference source
Replace i t  correctly by after-
sales personnel on site.
Replace i t  correctly by after-
sales personnel on site.
Adjust  i t  correctly  by a fter -
sales personnel on site.
Adjust  i t  correctly  by a fter -
sales personnel on site.
Eliminate  the  interferenc e 
source.
Y
N
N
N
N
N
Y
Y
Y
Y
N
Y