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8.5.5 FLAME DETECTOR
1. Disconnect AC power to the unit.
2. Remove the flame detector as per Section
7.3.
3. Check the detector for signs of erosion or
carbon build-up.
4. If the flame detector is eroded, replace it.
Otherwise, clean it using emery cloth.
5. Carbon build-up on the flame detector
indicates that unit may require combustion
calibration.
6. Check the combustion calibration settings as
per Sections 4.2 and 4.3.
8.5.6 IGNITION CIRCUIT
1. Disconnect AC power to the unit.
2. Close the manual leak detection valve,
located between the safety shut-off valve
and the differential pressure regulator, on
the unit's gas manifold.
3. Using a spare ignitor, connect the ignition
cable directly to the ignitor.
4. Ground the ignitor to the frame of the unit.
5. Reconnect AC power to the unit.
6. Start the unit.
WARNING !
ELECTRIC SHOCK HAZARD. THE
SECONDARY OF THE IGNITION
TRANSFORMER HAS A POTENTIAL OF
6000 VOLTS. DO NOT HOLD OR TOUCH
ANY IGNITION CIRCUIT COMPONENTS
WHILE TESTING.
7. At ignition an arc should be observed. It
should last for approximately 15 seconds.
8. If there is no arc, disconnect AC power to
the unit.
9. Remove the ignition cable and check it for
continuity or loose connections.
10. Replace the cable if there is no continuity or
if there is a loose connection.
TROUBLESHOOTING
11. If the ignition cable is okay, remove the
ignition transformer cover plate.
12. Referring to system schematic 161413 in
Appendix H, locate wires #12 and #29.
13. Connect an AC voltmeter across wires #12
and #29.
14. Reconnect AC power to the unit and start
the unit.
15. At the ignition cycle check for 120VAC
across wires #12 and #29.
16. If 120VAC is observed across wires #12 and
#29, replace the ignition transformer.
17. If 120VAC is not observed on the AC
voltmeter during the Ignition cycle,
disconnect AC power to the unit.
18. Disconnect the 9 pin connector from the
control panel, and wires #12 and #29 from
the ignition transformer.
19. Remove the cover plate from the AC wiring
box.
20. Referring to system schematic 161413 in
Appendix H, check wires #12 and #29 for
continuity.
21. If wires #12 and #29 have continuity, inspect
the pin on wire #12 in the 9 pin connector for
proper insertion or signs of wear.
22. Inspect the connector on wire #29 at the AC
wiring box end for a loose connection.
23. Make any necessary repairs.
24. After all wiring and connections have been
inspected or repaired, reconnect wires #12
and #29 to the ignition transformer.
Reconnect wire #29 to its proper position in
the AC wiring box.
25. Reconnect the 9 pin connector to the control
panel ensuring it is locked into place.
26. Reinstall the cover plates on the ignition
transformer and the AC wiring box.
27. Be sure to reinstall the spark ignitor and
ignitor contactor if necessary and reconnect
the ignition cable to the ignition transformer
and the ignition contactor.
28. Reopen the leak detection valve.
45
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