15
VIII - TROUBLESHOOTING
Label all wires prior to disconnection when ser-
vicing controls. Wiring errors can cause improp-
er and dangerous operation. Always disconnect
power to boiler before servicing. Failure to com-
ply could result in severe personal injury, death
or substantial property damage. Never jumper
(bypass) any device except for momentary test-
ing as outlined on the following pages of this
manual. Severe personal injury, death or sub-
stantial property damage can result.
CONTROL MODULE FUSES
IMPORTANT:
always
check control module fus
-
es before replacing control module or any major
components (blower, etc.) If one of these fuses is
blown, it can prevent control module or other com
-
ponents from operating.
Turn OFF power to boiler at external line switch.
1.
Remove jacket front panel.
2.
Remove control module cover.
3.
Inspect fuses F1 and F3 (shown below).
4.
The boiler is shipped with four spare fuses attached to
5.
the control module cover.
If necessary, replace open fuse (F1 is 115V, 5-amp fast-
6.
blow; F3 is 24V, 4-amp slow-blow).
F1 and F3 Fuses
WARNING
!
Install control module cover and jacket top front cover
7.
after fuse inspection.
Restore power to boiler at external line switch and verify
8.
boiler operation after completing boiler service.
CHECKING TEMPERATURE SENSORS
The boiler temperature sensors (outdoor, return water, and
1.
supply water) are all resistance-type devices.
The table below shows the correct resistance value for
2.
the sensor at various temperatures.
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
Use the resistance values at 32°F, 60°F, 70°F and 212°F
3.
to measure the sensor resistance at known tempera
-
tures (ice point, room temperature and sea level boiling
point). For ice point and boiling point, insert the sensor
in water at that temperature. Use an ohm meter to read
resistance value.
To check whether the control module is correctly sens
-
4.
ing temperature, you can use a resistance decade box.
Connect the decade box temporarily in place of a sensor
and use the control module “Information” mode to read
the temperature.
Do not jumper fuse or replace with any fuse ex-
cept as specified. Failure to comply could result
in severe personal injury, death or substantial
property damage.
WARNING
!