Weil-McLain EcoTec 80 Manual page 115

G -
®
ECO Tec
AS FIRED WATER BOILER
Troubleshooting
Check control fuses
ALWAYS check control fuses before replacing the
control or any major components (blower, etc.).
If one of these fuses is blown, it can prevent the
control or other components from operating.
1. Turn OFF power to boiler at external line switch. Then
remove the control access door.
2. Locate fuses using Figure 102.
3. Remove and inspect the seven (7) fuses (Items 1, 2, and 3,
Figure 102).
4. If necessary, replace one or more of the fuses:
a. Low voltage circuit fuse (Item 1) is a 3-amp 24VAC
fast-blow (Littelfuse 0287003).
b. Line voltage circuit fuses (Item 2) are 2.5-amp
120VAC fast-blow (Littelfuse 032602.5).
c. Line voltage circuit fuses (Item 3) are 4-amp 120VAC
fast-blow (Littelfuse 314004).
Do not jumper either fuse or replace with any fuse
except as specified. Failure to comply could result
in severe personal injury, death or substantial
property damage.
5. Reinstall the control access cover.
Checking temperature sensors
1. The boiler temperature sensors (Boiler In, Boiler Out, DHW
Out, Flue, Outdoor, and System Supply/Return) are all
resistance-type devices. Figure 101 shows the correct value
for the sensor at various temperatures. For dual sensors,
the temperature difference between the sensors must be no
more than 10°F.
2. Use the resistance values at 32°F, 60°F, 70°F and 212°F to
measure the sensor resistance at known temperatures (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 ohmmeter to read resistance value.
3. To check whether the control is correctly sensing temperature,
you can use a resistance decade box. Connect the decade box
temporarily in place of a sensor and read the corresponding
temperature on the control display. The temperature should
be close to the value corresponding to the input resistance.
Sensor resistance values
32 34265 37871 90
40 27834 30764 100
50 21630 23907 110
60 16944 18727 120
70 13372 14780 130
80 10629 11747 140
Part number 550-100-260/0520
(continued)
8504 9399 150 2517
6847 7568 160 2091
5545 6129 170 1744
4517 4992 180 1461
3698 4088 190 1229
3043 3364 200 1038
–
80/110/150/199
Control fuses
1
1 Fuse
3-Amp
24VAC
2782
2311
1928
1615
1359
1147
B M
OILER ANUAL
2
3
1 Fuse
4-Amp
120VAC
115