N80ESN/N80ESL(Series A): Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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flow to the burners, and de-energizing the 24-v humidifier
terminal 24VAC HUM. The inducer motor IDM will remain
energized for a 5-second post-purge period. Then turn off the
inducer motor and HUM (115-v) humidifier terminal. The
blower motor BLWM and air cleaner terminal EAC 1 will remain
energized for 90, 120, 150, or 180 seconds (depending on the
HEAT-OFF delay selection). The furnace control CPU is
factory-set for a 120-second Heat-Off Delay.
2.
Cooling Mode
(See
for thermostat connections.) The thermostat closes the
R-to-G-and-Y circuits. The R-to-Y circuit starts the outdoor unit,
and the R-to-G and Y circuits start the furnace blower motor
BLWM on COOL speed. The electronic air cleaner terminal EAC-1
is energized with 115 vac when the blower motor BLWM is
operating. When the thermostat is satisfied, the R-to-G-and-Y
circuits are opened. The outdoor unit will stop, and the furnace
blower motor BLWM will continue operating on the COOL speed
for an additional 90 sec. Cut jumper J2 to reduce the cooling
).
3.
Continuous Blower Mode
When the R-to-G circuit is closed by the thermostat, the blower
motor BLWM will operate on continuous-blower speed FAN.
Terminal EAC-1 is energized as long as the blower motor BLWM is
energized.
During a call for heat, the blower BLWM will stop during igniter
warm-up (17 sec), ignition, and blower-ON delay (25 sec), allowing
the furnace heat exchangers to heat up more quickly, then restarts at
the end of the blower-ON delay period at HEAT speed.
When the thermostat “calls for cooling”, the blower motor BLWM
will operate at COOL speed. When the thermostat is satisfied, the
blower motor BLWM will operate an additional 90 sec, on COOL
speed before reverting back to continuous blower speed.
When the R-to-G circuit is opened, the blower motor BLWM will
continue operating for an additional 5 sec, if no other function
requires blower motor BLWM operation.
4.
Heat Pump
When installed with a heat pump, the furnace control automatically
changes the timing sequence to avoid long blower off times during
demand defrost cycles. When the R-to-W-and-Y or
R-to-W-and-Y-and-G circuits are energized the furnace control
CPU will continue to turn on the blower motor BLWM at HEAT
speed, and begin a heating cycle. The blower motor BLWM will
remain on until the end of the prepurge period, then shut off for 24
sec then come back on at HEAT speed. When the W input signal
disappears, the furnace control begins a normal inducer post-purge
period and the blower switches to COOL speed after a 3 sec delay.
If the R-to-W-and-Y-and-G signals disappear at the same time, the
blower motor BLWM will remain on for the selected blower- OFF
delay period. If the R-to-W-and-Y signals disappear, leaving the G
signal, the blower motor BLWM will continue running the blower
motor at HEAT speed after the selected blower-OFF delay period is
completed.
Wiring Diagram
shows a schematic for the furnace wiring diagram.
Troubleshooting
Refer to the service label (see
). The Troubleshooting Guide (see
Fig. 51
) 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.
