Danger – Dunkirk Q95M-200 Modulating Condensing Boiler User Manual
Page 15
15
Control Module Fuses
Check control module fuses before replacing control module
or any major components (blower, etc.) If one of these
fuses is blown, it can prevent control module or other
components from operating.
1.
Turn OFF power to boiler at external line switch.
2.
Remove jacket front panel.
3.
Remove control module cover.
4.
Inspect fuses F1 and F3 (shown below).
5.
Boiler is shipped with four spare fuses attached to
control module cover.
6.
If necessary, replace open fuse (F1 is 115V, 5-amp
fast-blow; F3 is 24V, 4-amp slow-blow).
7.
Install control module cover and jacket top front cover
after fuse inspection.
8.
Restore power to boiler at external line switch and
verify boiler operation after completing boiler service.
Checking Temperature Sensors
1.
Boiler temperature sensors (outdoor, return water, and
supply water) are all resistance-type devices.
2.
Table 1 shows correct resistance value for sensor at
various temperatures.
3.
Use resistance values at 32°F, 60°F, 70°F and 212°F to
measure sensor resistance at known temperatures (ice
point, room temperature and sea level boiling point).
For ice point and boiling point, insert sensor in water
at that temperature. Use ohm meter to read resistance
value.
4.
To verify control module is correctly sensing
temperature, use a resistance decade box. Connect
decade box temporarily in place of sensor. Use control
module “Information” mode to read temperature.
9 - TROUBLESHOOTING
DANGER
Electric shock hazard! Disconnect power before
servicing. All service must be performed by a
trained, experienced service technician. Never
jumper (bypass) any device except for momentary
testing as outlined on the following pages of this
manual. Failure to follow these instructions WILL
result in death or serious injury
!
F1 and F3 Fuses
Temp
°F
Sensor Ohms
Temp
°F
Sensor Ohms
Min
Max
Min
Max
32
34,265
37,871
130
3,698
4,088
40
27,834
30,764
140
3,043
3,364
50
21,630
23,907
150
2,517
2,782
60
16,944
18,727
160
2,091
2,311
70
13,372
14,780
170
1,744
1,928
80
10,629
11,747
180
1,461
1,615
90
8,504
9,399
190
1,229
1,359
100
6,847
7,568
200
1,038
1,147
110
5,545
6,129
210
880
972
120
4,517
4,992
212
851
941
Table 1 - Sensor Resistance Values at Various
Temperatures