Weil-McLain CGA Series 2 Manual page 47

CGa Series 2 Gas-Fired Water Boiler — Boiler Manual
10b
Service & maintenance – annual start-up
❏ Cleaning boiler heating surfaces
6. Remove radiation plates hanging between sections.
7. Remove burners from base. Brush and vacuum burners to
remove all dust and lint. Verify that all burner ports are free
of debris.
8. Place newspapers in base of boiler to collect soot.
9. Clean between sections with wire flue brush.
10. Remove newspaper and soot. Vacuum or brush base and
surrounding area.
11a
Troubleshooting — components
Label all wires prior to disconnection when
servicing controls. Wiring errors can cause
improper and dangerous operation.
Never jumper (bypass) rollout thermal
fuse element or any other device except for
momentary testing as outlined in
shooting Charts
death or substantial property damage can
result.
Burner access panel must be in position
during boiler operation to prevent mo-
mentary flame rollout on ignition of main
flame. Severe personal injury or substantial
property damage will result.
See pages 48 through 56 for additional
troubleshooting information.
Before troubleshooting:
1. Have the following items:
a. Voltmeter that can check 120 VAC and 24 VAC.
b. Microammeter with a minimum scale range of
0-25.
c. Continuity checker.
d. U-tube manometer.
2. Check for 120 VAC (minimum 102 VAC to maximum
132 VAC) to boiler.
3. Make sure thermostat is calling for heat and contacts
(including appropriate zone controls) are closed. Check
for 24 VAC between thermostat wire nuts and ground.
Part Number 550-142-900/0519
Trouble-
. Severe personal injury,
(continued)
11. Reinstall radiation plates.
12. Replace collector box/transition assembly. Seal with sealant.
Obtain gas-tight seal to prevent flue gas spillage and carbon
monoxide emissions, resulting in severe personal injury or
death.
13. Replace insulation and jacket top panel.
14. Start up boiler following Section
Operating instructions
boiler
indicates improper gas combustion. If found, check for proper
combustion and make any necessary adjustments.
Temperature sensor
1. The boiler temperature sensor is a resistance-type device.
2. The Table 7, below shows the correct value for the sensor at
various temperatures.
3. 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 tem-
perature. Use an ohmmeter to read resistance value between
thermister # and thermistor common. See Figure 30, page 50,
for sensor plug details.
Table 7 Sensor resistance values
Sensor resistance values
Sensor ohms
Temp
(°F)
Min Max
32 34265 37871
40
27834 30764
50 21630 23907
60 16944 18727
70 13372 14780
80
10629 11747
90 8504 9399
100 6847 7568
110
5545 6129
(cont.)
6
of this manual and the
9b
(Section ). Excessive sooting
Sensor ohms
Temp
(°F)
Min Max
120 4517 4992
130
3698 4088
140 3043 3364
150 2517 2782
160 2091 2311
170
1744 1928
180 1461 1615
190 1229 1359
200
1038 1147
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