Service and Parts Manual (2019, 2020, 2021, 2022)

121 PB
COMPONENTS TESTING
Test System Flow
Cooling mode
The pressure is high.
Test system
pressure. Is the
pressure normal at the
low service port ?
The pressure is low.
Air remaining at the
yes
refrigerant system.
Recharge refrigerant
after air purging with
the vacuum
pump. Is the low
pressure normal?
NO
Recharge
yes
refrigerant .
The system needs
refrigerant.
Recharge refigerant.
Did the low pressure rise ?
The refrigerant system
blocked. Please check
the Capillary Tube （or
electronic expansion
valve) for blockage?
Check check valve and 4-
way valve.
Is the pressure is
close to static
NO
pressure?
NO
Unsolder the capillary tube
ASS'Y(or electronic expansion
valve). Clear the capillary tube
with compessed nitrogen.
yes
NO
yes
Heating mode
4-way valve clogged or
compressor exhaust blocked.
The pressure is high.
Test system
pressure. Is the pressure
normal at the high
pressure service port??
The pressure is low.
Air remaining at the
yes
refrigerant system.
Recharge refrigerant
after air purging with
the vacuum
pump. Is the high
pressure normal?
NO
yes
Recharge refrigerant
The system needs
refrigerant. Add refrigerant.
Is the pressure normal.
Is the pressure close
to static pressure?
yes
4-way valve clogged or
compressor exhaust blocked.
NO
Check heat exchanger and
4-way valve.
NO
Remove the back
panel."see"the
capillary tube1 and
defrosting?
yes
capillary tube2. Are
they
NO
The capillary tube
blocked. Unsolder the
capillary tube ASS'Y. Blow out
capillary tube1 and capillary
tube2 with compressed
nitrogen
.