Trane 4TVH0086FE000AA Service Manual page 118

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Insufficient refrigerant caused by
The system is blocked, caused by crushed
or bent pipe, blocked EXV or dirty filter
The indoor load is too large
System contains air or nitrogen
The condenser heat exchange is poor
Replace outdoor main PCB
Notes:
1. Compressor top temperature sensor and discharge pipe temperature sensor connections are ports CN4 and CN5 on the main PCB (labeled 3 and 4,
respectively, in Figure 5-2.1 in Part 5, 2.1 "Ports"). The discharge temperature switch connection is port CN18 on the main PCB (labeled 2 in Figure 5-2.1 in
Part 5, 2.1 "Ports").
2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor's resistance
characteristics table, the sensor has failed. Refer to Table 6-3.2 in Part 6, 3.1 "Temperature Sensor Resistance Characteristics".
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. An indoor load that is too large causes suction and discharge temperatures to be higher than normal. 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".
6. Air or nitrogen in the system causes discharge temperature to be higher than normal, discharge pressure to be higher than normal, compressor current to
be higher than normal, abnormal compressor noise and an unsteady pressure meter reading. 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".
7. In cooling mode check outdoor heat exchangers, fans and air outlets for dirt/blockages. In heating mode check indoor heat exchangers, fans and air outlets
for dirt/blockages.
refrigerant leakage 3
No
No
5
No
No
No
Add refrigerant and inspect the system
Yes
Inspect the system and fix the error. If the
Yes
filter is blocked by ice, the piping should
4
Make sure the combination ratio is less
Yes
Flush all refrigerant then vacuum the
Yes
6 system and recharge refrigerant. Add oil
Yes
Inspect the system and fix the error
7
117
for leaks
be cleaned
than 130%
to the system if it leaks