Mitsubishi Electric PUHZ-SW50VHA Service Manual page 38

10-8. HOW TO CHECK THE COMPONENTS
<Thermistor feature chart>
Low temperature thermistors
• Thermistor <Liquid> (TH3)
• Thermistor <2-phase pipe> (TH6)
• Thermistor <Ambient> (TH7)
Thermistor R0 = 15k" ± 3%
B constant = 3480 ± 2%
–
1
=15exp{3480(
t
R
273+t
0: 15 k"
30:
9.6 k"
10: 40:
20: 6.3 k"
25: 5.2 k"
Medium temperature thermistor
• Thermistor <Heat sink> (TH8)
Thermistor R50 = 17 k" ± 2%
B constant = 4150 ± 3%
1
=17exp{4150( 273+t – 323 )}
t
R
0: 180 k"
25: 50 k"
17 k"
50:
70: 8 k"
90: 4 k"
High temperature thermistor
• Thermistor <Discharge> (TH4)
• Thermistor <Comp. surface> (TH34)
Thermistor R120 = 7.465k" ± 2%
B constant = 4057 ± 2%
1
=7.465exp{4057( 273+t – 393 )}
t
R
20: 250 k" 70:
160 k" 80:
30:
104 k" 90:
40:
70 k" 100: 13.0 k"
50:
60: 48 k"
110:
OCH525C
1
)}
273
4.3 k"
3.0 k"
1
1
34 k"
24 k"
17.5 k"
9.8 k"
50
40
30
20
10
0
−20 −10 0 10 20 30 40 50
Temperature (:)
200
150
100
50
0
25
Temperature (:)
500
400
300
200
100
0
25
Temperature (:)
38
50 75 100 125
50 75 100 120