95
Procedure
H8
High pressure sensor connection on main
PCB is loose
1
Yes
Ensure the sensor is connected properly
No
High pressure sensor has short-circuited
or failed
2
Yes
Replace the sensor
No
Insufficient refrigerant caused by
refrigerant leakage
3
Yes
Add refrigerant and inspect system for
leaks
No
The low pressure side is blocked, caused
by crushed or bent pipe, closed EXV or
dirty filter
4
Yes
Inspect the system and fix the error. If the
filter is blocked by ice, the piping should
be cleaned
No
The evaporator heat exchange is poor
5
Yes
Inspect the system and fix the error
No
Replace the outdoor main PCB
Notes:
1. High pressure sensor connection is port CN17 on the main PCB (labeled 7 in Figure 5-2.1 in Part 5, 2.1 “Ports”).
2. Measure the resistance among the three terminals of the pressure sensor. If the resistance is of the order of mega Ohms or infinite, the pressure sensor
has failed.
3. An insufficiency of refrigerant causes compressor discharge temperature to be higher than normal, discharge and suction pressures to be lower than
normal and compressor current to be lower than normal, and may cause frosting to occur on the suction pipe. These issues disappear once sufficient
refrigerant has been charged into the system. For normal system parameters refer to Table 6-3.4 and 6-3.5 in Part 6, 3.2 “Normal Operating Parameters of
Refrigerant System”.
4. A low pressure side blockage causes compressor discharge temperature to be higher than normal, suction pressure to be lower than normal and
compressor current to be lower than normal, and may cause frosting to occur on the suction pipe. For normal system parameters refer to Table 6-3.4 and
6-3.5 in Part 6, 3.2 “Normal Operating Parameters of Refrigerant System”.
5. In cooling mode check indoor heat exchangers, fans and air outlets for dirt/blockages. In heating mode check outdoor heat exchangers, fans and air outlets
for dirt/blockages.
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