57
Thermistor R0 = 15k
'
± 3%
B constant = 3480 ± 2%
t (
:
): R
t
=15exp{3480( 273+t
–
273 )}
T (˚F): R
T
=15exp{3480( 273+(T– 32)/1.8
–
273 )}
10-7. HOW TO CHECK THE COMPONENTS
<Thermistor feature chart>
Low temperature thermistors
• Thermistor <Outdoor pipe> (TH3)
• Thermistor <Outdoor 2-phase pipe> (TH6)
• Thermistor <Outdoor> (TH7)
0
:
[32˚F]
15k
'
10
:
[50˚F]
9.6k
'
20
:
[68˚F]
6.3k
'
25
:
[77˚F]
5.2k
'
30
:
[86˚F]
4.3k
'
40
:
[104˚F]
3.0k
'
1
1
Thermistor R120 = 7.465k
'
± 2%
B constant = 4057 ± 2%
t (
:
): Rt =7.465exp{4057( 273+t
–
393)}
T (˚F): R
T
=7.465exp{4057( 273+(T– 32)/1.8
–
393 )}
1
1
20
:
[68˚F]
250k
'
30
:
[86˚F]
160k
'
40
:
[104˚F]
104k
'
50
:
[122˚F]
70k
'
60
:
[140˚F]
48k
'
70
:
[158˚F]
34k
'
80
:
[176˚F]
24k
'
90
:
[194˚F]
17.5k
'
100
:
[212˚F]
13.0k
'
110
:
[230˚F]
9.8k
'
High temperature thermistor
• Thermistor <Discharge> (TH4)
0
10
20
30
40
50
-20 -10 0
10 20 30 40 50
-4 -14 32 50 68 86 104 122
:
°
F
Temperature
Resistance (k
"
)
500
400
300
200
100
0
25
50
75
100
120
77
122
167
212
248
:
°
F
Temperature
Resistance (k
"
)
0
:
[32˚F]
180k
'
25
:
[77˚F]
50k
'
50
:
[122˚F]
17k
'
70
:
[158˚F]
8k
'
90
:
[194˚F]
4k
'
Thermistor R50 = 17k
'
± 2%
B constant = 4170 ± 3%
t (
:
): Rt =17exp{4170( 273+t
–
323)}
T (˚F): R
T
=17exp{4170( 273+(T– 32)/1.8
–
323 )}
1
1
Medium temperature thermistor
• Thermistor <Heatsink> (TH8)
200
150
100
50
0
25
50
75
100 110 125
77
122
167 212 230 257
:
°
F
Temperature
Resistance (k
"
)
1
1
1
1
1
1
