FAN NOT OPERATING WHEN PIPE IS ABOVE 60°C
NO
YES
YES
YES
NO
YES
NO
NO
YES
NO
NO
Is there and external clock fitted or external mains room stat
fitted?
Is there and external clock fitted or external mains room stat
fitted?
Check for mains going into fan plug
There must be a link between high voltage terminals 1 & 6 and
high voltage terminals 3 & 6. Make sure both links are present
There must be a link between
High Voltage
terminals 1 & 6 and
high voltage terminals 3 & 6. Make sure both links are present
Measure DC voltage (0 to 10V) within Low Voltage fan
connector (blue & yellow)
Make sure mains is present across high voltage terminals 1
& 2 and 3 & 4
Make sure mains is present across High Voltage terminals 1
& 2 and 2 & 3
Is measured voltage greater than 2V?
Check pipe and connections.
If sound, isolate from mains &
measure resistance across
plug J2 pins 5 & 6
Does the actual pipe temp.
match the approx. pipe
temp. for the measured
voltage in Table A?
Is measured resistance
greater than 11K?
Faulty fan
Faulty
PCB
Check sensor is fitted correctly.
If it is then replace sensor.
Faulty PCB
PCB is not seeing sensor.
Confirm by measuring
sensor resistance.
Replace sensor if
resistance is greater then
28K.
YES
YES
NO
In there 230 ~ 250 VAC across high voltage terminals 1 & 2?
If there 230 ~ 250 VAC across High Voltage terminals 1 & 2?
Make sure mains is present across High Voltage terminals 2 & 3
Is the MAF stat connected?
Is fan now running?
Link out low voltage terminals 3 & 4.
Measure voltage across Low Voltage terminals 5 & 6
Is measured voltage greater than 4.7V DC?
Make sure clock or room stat supplies mains voltage to high
voltage terminals 1 & 2. No mains - no fan operation (except for
summer vent)
DC VOLTAGE
ACROSS PIPE
SENSOR
APPROX. PIPE
TEMP. °C
DC VOLTAGE
ACROSS PIPE
SENSOR
APPROX. PIPE
TEMP. °C
DC VOLTAGE
ACROSS PIPE
SENSOR
APPROX. PIPE
TEMP. °C
DC VOLTAGE
ACROSS PIPE
SENSOR
APPROX. PIPE
TEMP. °C
3.24
10
2.13
33
1.26
56
0.73
79
3.19
11
2.08
34
1.23
57
0.71
80
3.14
12
2.04
35
1.20
58
0.70
81
3.09
13
1.99
36
1.17
59
0.68
82
3.04
14
1.95
37
1.15
60
0.66
83
2.99
15
1.91
38
1.12
61
0.65
84
2.94
16
1.87
39
1.09
62
0.63
85
2.89
17
1.83
40
1.07
63
0.63
86
2.84
18
1.79
41
1.04
64
0.60
87
2.79
19
1.75
42
1.02
65
0.59
88
2.75
20
1.71
43
0.99
66
0.58
89
2.70
21
1.67
44
0.97
67
0.56
90
2.65
22
1.63
45
0.95
68
0.55
91
2.60
23
1.59
46
0.92
69
0.54
92
2.55
24
1.56
47
0.90
70
0.53
93
2.50
25
1.52
48
0.88
71
0.51
94
2.45
26
1.49
49
0.86
72
0.50
95
2.40
27
1.45
50
0.84
73
0.49
96
2.36
28
1.42
51
0.82
74
0.48
97
2.31
29
1.39
52
0.80
75
0.47
98
2.26
30
1.35
53
0.78
76
0.46
99
2.22
31
1.32
54
0.76
77
0.45
100
2.17
32
1.29
55
0.75
78
TABLE A
www.johnsonandstarley.co.uk
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