Aerco KC Series Installation, Operation & Maintenance Instructions Manual page 56

NOTE:
Do not rotate the air/fuel valve with power
applied to the unit.
5. If the air/fuel valve does not rotate or is
extremely difficult to rotate, replace the
air/fuel valve.
6. Disconnect the 12-pin connector from the
control panel. Referring to schematic
161412 in Appendix F, check all wires for
continuity.
7. Check all the pins in the 12-pin connector for
proper insertion or signs of wear
8. If all connections, continuity, and the rotation
of the air/fuel valve in Step 4 were okay,
open the control box to expose the wiring
and components
9. Locate the air\fuel valve stepper motor driver
board.
10. Ensure the connectors and wires are not
loose and are making good contact.
11. If the wiring to the driver board is okay, place
a voltmeter across terminals 7 and 8 on the
back of the temperature controller.
12. Apply power to the unit.
13. Place the ON-OFF switch in the off position.
14. Measure the DC voltage across these two
terminals. It should be 15 V ± 2 V
15. Place the ON\OFF switch in the On position
16. Measure the DC voltage again it should be
approximately 3 volts DC during PURGE
and 1 to 1.3 volts during ignition.
17. If the voltage is correct
motor driver board.
18. If the voltage remains at 15 V ± 2 VDC
during PURGE or remains at 3 V DC during
ignition replace the relay board.
19. If the DC voltage is at 0 VDC
temperature control.
7.7.8 AIR/FUEL VALVE IGNITION
POSITION SWITCH
1. Disconnect electrical power to the unit.
,
replace the stepper
,
replace the
TROUBLESHOOTING
2. Remove the air/fuel valve cover
3. Referring to system schematic 161412 in
Appendix F, locate wires #60 and #61.
Remove wires #60 and #61 from the air/fuel
valve ignition position switch, noting their
position. (The air/fuel valve ignition position
switch is the one closest to the shell of the
unit.)
4. Place an ohm meter across the terminals of
the switch, where wires #60 and #61 were
located
5. Manually depress the switch and check the
ohm meter for continuity.
6. If the switch shows continuity, proceed to
Step 8.
7. If the switch does not show continuity,
replace the switch.
8. Disconnect the 12-pin connector from the
control panel.
9. Referring to system schematic 161412 in
Appendix F, locate wires #60 and #61.
Check wires #60 and #61 for continuity.
10. Check for loose connectors, at the switch
end of wires #60 and #61.
11. Check the 12-pin connector end for worn
and/or properly inserted pins.
12. If continuity, pins and connections are okay,
reattach wire #60 and #61 to the air/fuel
valve ignition position. Reconnect the 12-pin
connector to the control panel and restart the
unit.
13. If the system fault persists
local AERCO representative for further
assistance.
51
,
contact your