Mitsubishi Electric PUHZ-FRP71VHA Service Manual page 50

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)
Thermistor R0 = 15k' ± 3%
B constant = 3480 ± 2%
1
R =15exp{3480( –
t
273+t
0: 15k' 30:
10: 9.6k' 40:
20: 6.3k'
25: 5.2k'
Medium temperature thermistor
• Thermistor <Heatsink> (TH8)
Thermistor R50 = 17k' ± 2%
B constant = 4150 ± 3%
1
=17exp{4150( 273+t – 323 )}
R
t
0: 180k'
25: 50k'
50: 17k'
70: 8k'
90: 4k'
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 )}
R
t
20: 250k' 70:
30: 160k' 80:
40: 104k' 90:
50: 70k' 100: 13.0k'
60: 48k' 110:
OCH544
1
)}
273
4.3k'
3.0k'
1
1
34k'
24k'
17.5k'
9.8k'
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
50
50 75 100 125
50 75 100 120
Temperature ( )