Thermistor For The Temperature Of The Upper Part Of The Compressor - Hitachi FSXN Series Service Manual

11 Electrical checks of the
main parts
1 Inverter compressor
2 Thermistor holder
3 Thermistor fixing plate
4 Td thermistor (Td1) for the discharge gas temperature
5 Te thermistor (Liquid evaporation line)
6 Tg thermistor (gas evaporation line)
7 Tbg thermistor (Super-cooling bypass line)
8 Tchg thermistor (Super-cooling main line)
9 Butyl sheet
10 Plastic band
11 Thermistor (Te, Tg, Tbg, Tchg)
12 Thermistor holder
13 Thermo clip
14 Ta thermistor
15 Constant speed compressor
16 Td thermistor (Td2) for the discharge gas temperature (only for RAS-(14–18)FSXN

11.3.2 Thermistor for the temperature of the upper part of the compressor

1 The thermistor for the temperature of the upper part of the
compressor is installed for the purpose of preventing discharge
gas due to overheating. If the discharge gas temperature
increases excessively, the lubricating oil deteriorates and loses
its properties and consequently, the compressor's life is
shortened.
2 If the discharge gas temperature increases excessively, the
compressor temperature
compressor motor will burn out.
3 When the temperature of the upper part of the compressor
increases during heating operation, the unit is controlled
according to the following method.
a The expansion valve of the outdoor unit opens to return the
liquid refrigerant to
accumulator, decreasing the compressor's temperature.
b If the temperature of the upper part of the compressor
increases over 132 °C, even if the expansion valve opens,
the compressor stops in order to protect itself. This procedure is also available in the cooling operation.
4 If the temperature of the upper part of the compressor increases excessively, protection control will be activated and
the compressor will stop according to the following method:
Operation
Cooling
Heating
Defrosting
337
SMGB0065 rev. 1 - 12/2010
increases. Consequently,
the compressor through
Temperature of the upper part of the
compressor
Over 132 °C
Over 140 °C
Over 132 °C
Over 140 °C
Over 132 °C
200
200
R25 = 200k
B = 3920k
100
72.3
the
0
25 30
Temperature (°C)
Resistance Characteristics of Thermistor
for discharge Gas Overheating Protection
the
10 minutes (continuous)
5 seconds (continuous)
10 minutes (continuous)
5 seconds (continuous)
5 seconds (continuous)
14.2
5.3
100 132 150
Stopping period
11