Service Manual

58
OCH636B
Thermistor R0 = 15 k" ± 3%
B constant = 3480 ± 2%
t (°C): Rt =15exp{3480(
273+t
–
273
)}
T (°F): RT =15exp{3480(
273+(T– 32)/1.8
–
273
)}
10-7. HOW TO CHECK THE COMPONENTS
<Thermistor feature chart>
Low temperature thermistors
• Thermistor <Liquid> (TH3)
• Thermistor <2-phase pipe> (TH6)
• Thermistor <Ambient> (TH7)
• Thermistor <Suction> (TH32)
32°F [0°C] 15 k"
50°F [10°C] 9.6 k"
68°F [20°C] 6.3 k"
77°F [25°C] 5.2 k"
86°F [30°C] 4.3 k"
104°F [40°C] 3.0 k"
1
1
Thermistor R120 = 7.465 k" ± 2%
B constant = 4057 ± 2%
t (°C): Rt =7.465exp{4057(
273+t
–
393
)}
T (°F): R
T =7.465exp{4057(
273+(T– 32)/1.8
–
393
)}
1
1
68°F [20°C] 250 k"
86°F [30°C] 160 k"
104°F [40°C] 104 k"
122°F [50°C] 70 k"
140°F [60°C] 48 k"
158°F [70°C] 34 k"
176°F [80°C] 24 k"
194°F [90°C] 17.5 k"
212°F [100°C] 13.0 k"
230°F [110°C] 9.8 k"
High temperature thermistor
• Thermistor <Comp. surface> (TH33)
• Thermistor <Discharge> (TH4)
0
10
20
30
40
50
−20 −10 0 10 20 30 40 50
−4 −14 32 50 68 86 104122
°C
°F
Temperature
Resistance (k")
500
400
300
200
100
0
25
50 75 100 120
77
122 167 212 248
°C
°F
Temperature
Resistance (k")
32°F [0°C] 180 k"
77°F [25°C] 50 k"
122°F [50°C] 17 k"
158°F [70°C] 8 k"
194°F [90°C] 4 k"
Thermistor R50 = 17 k" ± 2%
B constant = 4150 ± 3%
t (°C): Rt =17exp{4150(
273+t
–
323
)}
T (°F): R
T=17exp{4150(
273+(T– 32)/1.8
–
323
)}
1
1
Medium temperature thermistor
• Thermistor <Heat sink> (TH8)
200
150
100
50
0
25 50 75 100 110 125
77 122 167 212 230 257
°C
°F
Temperature
Resistance (k")
1 1
1 1
1 1