Temperature Sensors; Electronic Components - IBC VFC 15-150 Manual

Return water temperature sensor
10KΩ sensors supplied with boiler
2 x Water temperature sensors - (L)
1 x Outdoor sensor - (R)
See table #8 for resistance values
5-2
VFC 15-150 - VFC 45-225 MODULATING GAS BOILERS
5.2

eleCtroniC CoMPonents

this section details the method for troubleshooting the non-standard electronic
components on the boiler including the electronic differential air pressure sensor
and the temperature sensors.

5.2.1 Temperature Sensors

the resistance of the temperature sensors varies inversely with temperature. to
test, measure the temperature of the sensed environment and compare with the
value derived from the measurement of the resistance (obtained by connecting a
good quality test meter capable of measuring up to 5,000 kΩ (5,000,000Ω) at the
controller end of the sensor lead).
to obtain a resistance reading, remove power to the boiler. locate the blue
2-wire leads coming from the thermistors, which are affixed to the boiler supply
and return piping to the right of the heat exchanger. disconnect the Molex
connectors located approx. 6" from the sensors. Place multi-meter probes into
Molex socket. do not apply voltage to the sensor as damage may result.
sensors are sensitive to excess binding force, which can distort the internal
dielectric isolation. Use modest tension only when affixing sensor to pipe.
TEMPERATURE
°F
0 -18
5 -15
10 -12
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
Table 8: Temperature Sensor resistance values
RESISTANCE
°C Ω
85,362
72,918
62,465
-9 53,658
-7 42,218
-4 39,913
-1 34,558
2 29,996
4 26,099
7 22,763
10 19,900
13 17,436
16 15,311
18 13,474
21 11,883
24 10,501
27 9,299
29 8,250
32 7,334
35 6,532
INSTALLATION AND OPERATION INSTRUCTIONS
TEMPERATURE RESISTANCE
°F °C
100 38
105 41
110 43
115 46
120 49
125 52
130 54
135 57
140 60
145 63
150 66
155 68
160 71
165 74
170 77
175 79
180 82
185 85
190 88
195 91
Ω
5,828
5,210
4,665
4,184
3,760
3,383
3,050
2,754
2,490
2,255
2,045
1,857
1,689
1,538
1,403
1,281
1,172
1,073
983
903