INSTALLATION AND OPERATION INSTRUCTIONS
5-2
SL 30-175, SL 45-260 MODULATING GAS BOILERS
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. For the supply water
and vent temperature sensors, remove the wire leads by disconnecting their
respective Molex connectors. Place multi-meter probes into sensor’s female
Molex connector socket. do not apply voltage to the sensor (damage may result).
For the return water temperature sensor, locate the blue 2-wire leads coming
from the strap on sensor on the return pipe. disconnect the Molex connector
located approx. 6" from the sensor. Place multi-meter probes into the sensor’s
female Molex connector socket. do not apply voltage.
TEMPERATURE
RESISTANCE
TEMPERATURE
RESISTANCE
°F
°C
Ω
°F
°C
Ω
0
-18
85,362
100
38
5,828
5
-15
72,918
105
41
5,210
10
-12
62,465
110
43
4,665
15
-9
53,658
115
46
4,184
20
-7
42,218
120
49
3,760
25
-4
39,913
125
52
3,383
30
-1
34,558
130
54
3,050
35
2
29,996
135
57
2,754
40
4
26,099
140
60
2,490
45
7
22,763
145
63
2,255
50
10
19,900
150
66
2,045
55
13
17,436
155
68
1,857
60
16
15,311
160
71
1,689
65
18
13,474
165
74
1,538
70
21
11,883
170
77
1,403
75
24
10,501
175
79
1,281
80
27
9,299
180
82
1,172
85
29
8,250
185
85
1,073
90
32
7,334
190
88
983
95
35
6,532
195
91
903
Table 9: Temperature Sensor resistance values
5.2
Return water temperature sensor
Supply water temperature sensor
See table #9 (right), to calculate
resistance values for all 10KΩ
sensors supplied with boiler (above)
Outdoor sensor
Vent temperature sensor -
optional
Summary of Contents for SL 30-175
Page 76: ...NOTES...