Cooling Cycle; Fan Mode; Troubleshooting; Maintenance - Nordyne 80+ AFUE *SA Installation Instructions Manual

Cooling Cycle

1. The thermostat calls for cooling by energizing the Y
terminal with 24VAC.
2. The control energizes the blower in the cooling speed
and sends 24VAC to the contactor in the condensing
unit.
3. When the thermostat removes the call for cooling,
the contactor in the outdoor condensing unit is de-
energized and the control continues to run the fan for
a period of 60 seconds.

Fan Mode

• When the thermostat energizes the G terminal for
continuous fan (without calling for heat or cooling), the
indoor fan is energized on the selected FAN speed.
• If a call for cooling occurs during continuous fan, the
blower will switch over to the selected COOL speed.
• If the W terminal receives a call for heat during continuous
fan, the blower will de energize.
• A call for fan is ignored while in lockout.

TROUBLESHOOTING

If the furnace fails to operate check the following:
• Is the thermostat operating properly?
• Are the blower compartment door(s) in place?
• Is the furnace disconnect closed?
• Has the circuit breaker tripped or the control board
fuse burned open?
• Is the gas turned on?
• Are any manual reset switches open?
• Is the fi lter dirty or plugged?
• Is the fl ame sensor coated? (Remove and clean with
steel wool).
• Are all the LED's on the furnace control board constantly
ON? If not, refer to Table 3 or the wiring diagram (Figure
18, page 31) to determine fault condition.
IMPORTANT NOTE: The furnace will lock out after 5
failed attempts for ignition and will try again every
hour if the call for heat remains.
• If the Inducer Blower is operating, and items above
have been verifi ed, check the Blower Limit Switch and
reset if necessary. See Figure 19 or 20 (page 35) for
component location.
• If the furnace operates when the Blower Limit Switch is
reset, contact a qualifi ed service technician to identify
and repair the problem.
• If the furnace still doesn't operate, check the Flame
Roll-out Switches and reset if necessary. See Figure
19 or 20 for component location.
• If the furnace operates when the Flame Rollout Switch
is reset, contact a qualifi ed service technician to identify
and repair the problem.
22
Diagnostic Description
Control Fault (No Power)
L1/Neutral Polarity Fault
1 Hour Lockout
Normal Operation
Pressure Switch Closed Fault
Pressure Switch Open Fault
Open Limit Switch Fault
Motor Fault
Diagnostic Description
Low Flame Sensor Signal
Flame Present
Table 3. Control Board Fault Conditions

MAINTENANCE

WARNING:
These maintenance instructions are primarily
intended to assist qualified technicians
experienced in the proper maintenance and
operation of this appliance.
Proper maintenance is most important to achieve the best
performance from a furnace. Follow these instructions for
years of safe, trouble free operation.
• Always reinstall the doors on the furnace after servicing
or cleaning/changing the fi lters. Do not operate the
furnace without all doors and covers in place.
• Verify the thermostat is properly installed and is not being
affected by drafts or heat from lamps or other appliances.
• To achieve the best performance and minimize equipment
failure it is recommended that a yearly maintenance
checkup be performed. At a minimum, this check should
include the following items:
Air Filter(s)
WARNING:
Never operate the furnace without a fi lter in
place. Dust and lint can build up on internal
components, resulting in loss of effi ciency,
equipment damage, and possible fi re.
Note: Air fi lter(s) are not supplied with the furnace as
shipped from the factory. The installer must provide a
high velocity fi lter and rack for a fi lter in the return air
duct adjacent to the furnace, or in a return air grill to the
furnace. It is recommended that fi lters be cleaned or
replaced monthly. New or newly renovated homes may
require more frequent changing until the construction
dust has minimized.
Green LED Red LED
Off Off
Flash Flash
Alternating Flash
On On
On Flash
Flash On
Flash Off
On Off
Yellow LED
Continuous Flash
On