Weil-McLain WM97+110, Руководство пользователя

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Part number 550-142-085/0712
– 101 –
WM97+
gas
-
fired water boiler
— Boiler Manual
Troubleshooting
(continued)
Check WM97+ control fuses
ALWAYS check WM97+ control fuses before replacing
WM97+ control or any major components (blower, etc.). If
one of these fuses is blown, it can prevent WM97+ control
or other components from operating.
1. Turn OFF power to boiler at external line switch. Then remove the
jacket door.
2. Access the WM97+ control fuses.
a. See Figure 105. Rotate item 1, the inlet air silencer, about 45 degrees
so it will be out of the way.
b. Remove the two screws, item 4.
c. Note the three slots (1, 2 and 3) on either side of the jacket. Lift
the control housing (item 2) until the top support arms are aligned
with slot 2, as shown. Pull the top of the housing forward so the
upper arms swing free. Continue rotating the control housing until
it rests on the jacket lower flange as in Figure 106.
d. Disconnect the ignition wire (at item 7). Remove the control hous-
ing back cover (item 6) by pressing the retainer clips (item 5), then
lifting and pulling cover forward.
3. Remove and inspect the two fuses (items 8 and 9, Figure 107).
4. If necessary, replace one or both of the fuses:
a. Low voltage circuit fuse is 3-amp fast-blow (Littelfuse 326012P).
b. Line voltage circuit fuse is 12-amp slow-blow (Littelfuse 257003).
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 control housing cover and return control housing to normal
position. Replace screws (item 4) and reconnect ignition cable at item 7.
Checking temperature sensors
1. The boiler temperature sensors (flue, outdoor, return water and supply
water) are all resistance-type devices. Figure 104 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 resis-
tance value.
3. To check whether the WM97+ control is correctly sensing temperature,
you can use a resistance decade box. Connect the decade box temporar-
ily in place of a sensor and read the corresponding temperature on the
WM97+ control display. The temperature should be close to the value
corresponding to the input resistance.
Figure 104
Sensor resistance values
Temp
(°F)
Sensor ohms Temp
(°F)
Sensor ohms Temp
(°F)
Sensor ohms
Min Max Min Max Min Max
32 34265 37871 90 8504 9399 150 2517 2782
40 27834 30764 100 6847 7568 160 2091 2311
50 21630 23907 110 5545 6129 170 1744 1928
60 16944 18727 120 4517 4992 180 1461 1615
70 13372 14780 130 3698 4088 190 1229 1359
80 10629 11747 140 3043 3364 200 1038 1147
Figure 105
Control housing lifted to slot 2 (jacket
door removed and inlet air silencer
rotated out of the way) (WM97+70
shown)
Figure 106
Control housing rotated forward
(WM97+70 shown)
Figure 107
Control housing with back removed
— close-up of WM97+ control fuse
location on the control board