Johnson Controls HVWHP072B32S - Page 245

(Main Parts)
MAINTENANCE
SM-18006
4-95
(3) Thermistor for Entering Water Temperature “Ta” (THM7)
The thermistor resistance characteristics are shown in the gure below.
(4) Thermistor for Evaporation Liquid Line “Te1, Te2” (THM10, 11) and Evaporation Gas Line “Tg” (THM12)
Temperature of Water Source Unit
The characteristics for the thermistor are the same as those of the entering water temperature
thermistor shown in the gure below.
(5) Thermistor for Subcooler “Tsc” (THM23) and Liquid Stop Valve “Tchg” (THM17) Temperature
of Water Source Unit
The characteristics for the thermistor are the same as those of the entering water temperature
thermistor shown in the gure below.
(6) Thermistor for Electrical Box Temperature “Ts” (THM14)
The characteristics for the thermistor are the same as those of the entering water temperature
thermistor shown in the gure below.
0.9V
1.4V
2.0V
2.6V
3.2V
3.6V
4.0V
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
0
10
20
30
40
50
60
70
80
90
Output Voltage [VDC]
Ambient Temperature T [ºF (ºC)]
Thermistor Characteristics
Thermistor Resistance [kΩ]
Thermistor Resistance R
T
[kΩ]
0
(-18)
10
(-12)
20
(-7)
30
(-1)
40
(4)
50
(10)
60
(16)
R
25
= 200kΩ
(When T = 77ºF (25ºC), RT = 200kΩ
B = 3920K
R
T
= R
25
• exp B(1/T[K] - 1/298)
26.7kΩ
48.3kΩ
15.4kΩ
9.3kΩ
70
(21)
80
(27)
90
(32)
100
(38)
110
(43)
120
(49)
130
(54)
140
(60)
5.8kΩ
2.5kΩ
3.7kΩ
Output Voltage [VDC]