→ELECTRICAL CONTROLS AND WIRING
There may be more than 1 electrical supply to the unit. Check accessories and cooling unit for additional electrical supplies.
The electrical ground and polarity for
NOTE: If the polarity is not correct, the STATUS LED on the control center will flash rapidly and prevent the furnace from operating. The control system also requires an earth ground for proper operation of the control board and
The
With power to the unit disconnected, check all electrical connec- tions for tightness. Tighten all screws on electrical connections. If any smoky or burned connections are found, disassemble the connection, clean all parts, strip wire, and reassemble properly and securely.
Reconnect electrical power to the unit and observe unit through 1 complete operating cycle. Electrical controls are difficult to check without proper instrumentation; if there are any discrepancies in the operating cycle, contact your dealer and request service.
For an explanation of fault codes, refer to service label located on blower access door or Fig. 13, and the troubleshooting guide.
The control center stores 1 fault code (the last fault to occur) for a period of 48 hrs or until the 115- or
NOTE: Removing blower access door will open blower access door switch and terminate
1. To retrieve fault code, proceed with the following:
NOTE: NO thermostat signal may be present at control center, and all blower time delay off periods must be completed.
a.Leave
b.Look into blower access door sight glass for current LED status.
NOTE: Leave blower access panel installed to maintain power to control center to view current LED status.
c.Remove control access door.
d.BRIEFLY remove either wire from the main limit switch until LED goes out, then reconnect it.
NOTE: If wire to main limit is disconnected longer than 4 sec, main blower starts, and retrieval request is ignored.
2.When above items have been completed, the following will occur:
a.LED flashes a fault code 4 times. Record this fault code for further troubleshooting.
b.Inducer motor operates for 10 sec, then turns off.
c.Hot surface ignitor is energized for 15 sec, then de- energized.
d.Main blower operates at cooling speed for 10 sec, then turns off.
e.Main blower operates at heating speed for 10 sec, then turns off.
Items a through e above will assist in furnace troubleshooting since all components are functionally operated except the gas valve. This procedure is also referred to as "Component Test."
3.Operate furnace through 1 heat cycle to test for proper operation and check LED status.
4.If furnace is operating properly and LED indicates proper operation, replace control access door.
5.Component Test can also be initiated by performing the following:
a.Remove control access door.
b.Remove blower access door.
c.Manually close blower access door switch.
Blower access door switch opens
d. BRIEFLY short (jumper) TEST,
NOTE: If TEST to Com terminals are jumpered longer than 2 sec, LED will flash rapidly, and retrieval request will be ignored.
e.Component Test will function as described in item 2 above.
f.Check LED status.
g.If LED status indicates proper operation, release blower access door switch, replace blower access door, and replace control access door.
TROUBLESHOOTING
Refer to the service label. (See Fig. 13.) Pages 10 and 11 contain a troubleshooting guide. This guide can be a useful tool in isolating furnace operation problems. Beginning with the word "Start," answer each question and follow the appropriate arrow to the next item.
The guide will help to identify the problem or failed component. After replacing any component, verify correct operation sequence.
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