Mitsubishi Electric CITY MULTI PUMY-P112VKM6 Service Manual page 92

8-8. How to check the components
8-8-1. Thermistor feature chart
■ Low temperature thermistors
• TH2 (HIC pipe)
• TH3 (Outdoor liquid pipe)
• TH6 (Suction pipe)
• TH7 (Ambient)
Thermistor R0 = 15 kΩ ± 3 %
B constant = 3480 ± 1 %
R =15exp{3480(
t
Temperature
0°C [32 °F ]
10°C [50 °F ]
20°C [68 °F ]
25°C [77 °F ]
30°C [86 °F ]
40°C [104 °F ] 3.0 kΩ
■ Medium temperature thermistor
• TH8 (Heat sink)
Thermistor R50 = 17 kΩ ± 2 %
B constant = 4150 ± 3 %
R =17exp{4150(
t
Temperature
0°C [32°F]
25°C [77°F]
50°C [122°F] 17 kΩ
70°C [158°F] 8 kΩ
90°C [194°F] 4 kΩ
■ High temperature thermistor
• TH4 (Compressor)
Thermistor R120 = 7.465 kΩ ± 2 %
B constant = 4057 ± 2 %
R =7.465exp{4057(
t
Temperature
20°C [68 °F ]
30°C [86 °F ]
40°C [104 °F ] 104 kΩ
50°C [122 °F ] 70 kΩ
60°C [140 °F ] 48 kΩ
70°C [158 °F ] 34 kΩ
80°C [176 °F ] 24 kΩ
90°C [194 °F ] 17.5 kΩ
100°C [212 °F ] 13.0 kΩ
110°C [230 °F ] 9.8 kΩ
OCH790 _92
1 1
– )}
273+t 273
Resistance value
15 kΩ
9.6 kΩ
6.3 kΩ
5.2 kΩ
4.3 kΩ
1 1
– )}
273+t 323
Resistance value
180 kΩ
50 kΩ
1 1
– )}
273+t 393
Resistance value
250 kΩ
160 kΩ
50
40
30
20
10
0
−20 −10 0 10 20 30 40 50
−4 −14 32 50 68 86 104 122
Temperature
200
150
100
50
0
25 50 75 100 125
257 (°F)
77 122 167 212
Temperature
500
400
300
200
100
0
25 50 75 100
77 122 167 212
Temperature
(°C)
(°F)
(°C)
120 (°C)
(°F)
248