Aerco KC Series Installation, Operation & Maintenance Instructions Manual page 49

2. If the gas supply valves were open, restart
the unit.
3. Remove the cover to the Air Fuel Valve.
Ensure that the Air Fuel Valve rotates to the
ignition position, and engages the ignition
position switch. If the air\fuel valve does not
rotate to the ignition position
Section 7.7.7.
4. If the air\fuel valve rotates and engages the
ignition position switch during the trial for
ignition, then visually watch/inspect the
safety shutoff valve, through the window on
the actuator half, to determine if it is
opening.
NOTE:
At the ignition cycle, the low fire switch is
made, and the safety shutoff valve is
energized. The OPEN disk in the safety
shut-off valve actuator window should
slowly move downward indicating that the
valve is operating correctly. If the valve
does not open, proceed to Section 7.5.3
5. If the safety shutoff valve opens
spark ignitor as per Section 7.5.4 and the
flame detector, as per Section 7.5.5.
6. If the spark ignitor and flame detector are
okay, or require replacement and the flame
fault persists, check the ignition circuit as per
Section 7.5.6.
7. If the flame fault persists after checking the
above, measure the flame detector lead
voltage as per Section 7.5.8.
8. If the flame fault persists, after checking the
above, remove the burner and inspect for
debris.'
9. If the flame fault persists after the above,
replace the combustion control.
7.5.3 SAFETY SHUTOFF VALVE
1. Start the unit.
2. When the starting sequence reaches the
Ignition trial cycle, observe the response of
the safety shutoff valve through the window
in the actuator portion
3. If the actuator does not open the valve,
disconnect electrical power to the unit.
,
proceed to
,
check the
44
TROUBLESHOOTING
4. Remove the actuator portion from the valve
body and inspect for signs of leaking
hydraulic fluid.
5. If the actuator is not leaking, set it back on
the valve body and remove the cover plate
exposing the control wiring.
6. Temporarily re-secure the actuator to the
valve body with the control wiring facing
outward for easy access.
7. Referring to system schematic 161412 in
Appendix F, connect an AC voltmeter across
wires #14 and #28.
8. Restore electrical power to the unit.
9. Start the unit.
10. At the ignition trial cycle 120 VAC should be
observed on the AC voltmeter.
11. If 120 VAC is observed on the voltmeter,
replace the safety shutoff valve actuator.
12. If 120 VAC is not observed on the AC
voltmeter, disconnect electrical power to the
unit.
13. Disconnect the 9-pin connector from the
control panel, and remove the cover from
the AC wiring box.
14. Referring to system schematic 161412 in
Appendix F, locate wire's #14, #28 and #27
and check each for continuity.
15. Check each wire for loose connectors at the
safety shut-off valve end. Check wires #28
and #27 for loose connectors in the KC1000
AC wiring box
16. Check the pin on wire #9 at the 9-pin
connector end, for proper insertion or wear.
17. If all wires show continuity and all
connections are okay, reconnect wire's #14,
#28 and #29 to the safety shutoff valve and
wires #28 and #29 to their proper locations
in the AC wiring box.
18. Replace the cover plates on the safety
shutoff valve actuator and the AC wiring box.
19. Reconnect the 9-pin connector to the control
panel ensuring that it locks into place.