TM081 Rheem 834 Series Hydroelectric CFGWH Service Instructions
REV: AA Issued: 22/02/17
This document is stored and maintained electronically by Rheem Technical Support. All printed copies are deemed uncontrolled.
39
Fault Finding Tests
Fault Finding Test 1
Testing the Hot Water Outlet Temperature Sensor
The hot water outlet temperature sensor is an NTC type thermistor. The resistance value
of the thermistor will change according to the detected temperature and the sensor can be
tested as follows:
1.
Isolate water supply to heater to prevent heater
from operating.
2. Disconnect sensor wiring plug and using a
multimeter set on the
kΩ scale, measure between
the two pins on the disconnected sensor plug.
3. Convert the k
Ω value obtained in step 2 to a
temperature value using the 'Sensor Temperature /
Resistance Table’ shown below.
4. Use a spot thermometer to measure the
temperature at the sensor location and compare
this value to the reading taken in steps 2 and 3
(sensor detected temperature). Allow for a
tolerance of ± 2ºC.
Note: If a spot thermometer is not available or the temperature at the sensor cannot be
accurately measured, remove sensor from sensor well (refer to component replacement
procedure 24 on page 59) so that sensor detects the ambient air temperature and
measure the ambient air temperature at the sensor using a thermometer.
Sensor Temperature / Resistance Table
ºC
kΩ
ºC
kΩ
ºC
kΩ
ºC
kΩ
ºC
kΩ
0
23.73
20
10.31
40
4.90
60
2.52
80
1.38
1
22.71
21
9.91
41
4.74
61
2.44
81
1.34
2
21.73
22
9.53
42
4.57
62
2.37
82
1.31
3
20.81
23
9.17
43
4.42
63
2.29
83
1.27
4
19.92
24
8.83
44
4.27
64
2.22
84
1.24
5
19.09
25
8.49
45
4.12
65
2.16
85
1.20
6
18.29
26
8.18
46
3.99
66
2.09
86
1.17
7
17.52
27
7.87
47
3.85
67
2.03
87
1.14
8
16.80
28
7.58
48
3.73
68
1.97
88
1.11
9
16.11
29
7.30
49
3.60
69
1.91
89
1.08
10
15.45
30
7.04
50
3.48
70
1.85
90
1.05
11
14.82
31
6.78
51
3.37
71
1.80
91
1.02
12
14.22
32
6.54
52
3.26
72
1.75
92
0.99
13
13.65
33
6.30
53
3.16
73
1.69
93
0.97
14
13.10
34
6.08
54
3.05
74
1.65
94
0.94
15
12.58
35
5.86
55
2.96
75
1.60
95
0.92
16
12.09
36
5.65
56
2.86
76
1.55
96
0.89
17
11.61
37
5.45
57
2.77
77
1.51
97
0.87
18
11.16
38
5.26
58
2.69
78
1.46
98
0.85
19
10.72
39
5.08
59
2.60
79
1.42
99
0.83
