yes
[39-0, 39-1] low pressure too low and compression ratio too high
no
no
no
yes
yes
no
open stop valve
re-connect the terminals
yes
check if system is lack
of refrigerant
check if terminal of
electronic expansion valve
coil is fixed well
check if piping system is
clogged
if actual pressure is in
conformance with the measured
data by sensor
recharge refrigerant
check if stop valve is open
fully
replace pressure sensor
yes
clear the piping
yes
[39-2] compression ratio too low
no
no
yes
yes
check compressor
check if 4-way valve is
interconnected
if actual pressure is in
conformance with the measured
data by sensor
replace 4-way valve
check if compressor
running current is normal
replace pressure sensor
84