How To Check The Components; Thermistor Feature Chart; Low Temperature Thermistors; Medium Temperature Thermistor - Mitsubishi Electric PUMY-P250YBM Technical & Service Manual

8-7. HOW TO CHECK THE COMPONENTS

<Thermistor feature chart>

Low temperature thermistors

• Thermistor <HIC Pipe> (TH2)
• Thermistor <Outdoor Liquid Pipe> (TH3)
• Thermistor <Suction Pipe> (TH6)
• Thermistor <Ambient> (TH7)
Thermistor R0 = 15 kΩ ± 3 %
B constant = 3480 ± 1 %
1
R =15exp{3480( –
t
273+t 273
0°C 15 kΩ 30°C
10°C 9.6 kΩ 40°C
20°C 6.3 kΩ
25°C 5.2 kΩ

Medium temperature thermistor

• Thermistor <Heat Sink> (TH8)
Thermistor R50 = 17 kΩ ± 2 %
B constant = 4150 ± 3 %
1
R =17exp{4150( –
t
273+t
0°C 180 kΩ
25°C 50 kΩ
50°C 17 kΩ
70°C 8 kΩ
90°C 4 kΩ
High temperature thermistor
• Thermistor <Compressor> (TH4)
Thermistor R120 = 7.465 kΩ ± 2 %
B constant = 4057 ± 2 %
1
R =7.465exp{4057(
t
273+t
20°C 250 kΩ 70°C
30°C 160 kΩ 80°C
40°C 104 kΩ 90°C
50°C 70 kΩ 100°C
60°C 48 kΩ 110°C
OCH760
1
)}
4.3 kΩ
3.0 kΩ
1
)}
323
1
)}
–
393
34 kΩ
24 kΩ
17.5 kΩ
13.0 kΩ
9.8 kΩ
50
40
30
20
10
0
-20 -10 0 10 20 30 40 50
200
150
100
50
0
500
400
300
200
100
0
99
Temperature (°C)
25 50 75 100 110 125
(°C)
Temperature
50 75 100
25
Temperature (°C)
120