Sequence Of Operation; Wiring Diagrams; Troubleshooting - Carrier N80ESN Series Installation Instructions Manual

lay contacts GVR close to energize the gas valve GV,
the gas valve opens, The gas valve GV permits gas
flow to the burners where it is ignited by the HSI. Five
seconds after the GVR closes, a 2- -second flame prov-
ing period begins. The HSI igniter will remain ener-
gized until the flame is sensed or until the 2- -second
flame proving period begins.
d. Flame- -Proving- - When the burner flame is proved at
the flame- -proving sensor electrode FSE, the furnace
control CPU begins the blower- -ON delay period and
continues to hold the gas valve GV open. If the burner
flame is not proved within two seconds, the control
CPU will close the gas valve GV, and the control CPU
will repeat the ignition sequence for up to three more
Trials- -For- -Ignition before going to Ignition- -Lockout.
Lockout will be reset automatically after three hours or
by momentarily interrupting 115 vac power to the fur-
nace, or by interrupting 24 vac power at 24VAC or
COM to the furnace control CPU (not at W, G, R, etc.)
If flame is proved when flame should not be present,
the furnace control CPU will lock out of Gas- -Heating
mode and operate the inducer motor IDM until flame
is no longer proved.
e. Blower- -On Delay- - If the burner flame is proven, the
blower motor is energized on HEAT speed 25 sec after
the gas valve GV is energized.
Simultaneously, the electronic air cleaner terminal
EAC- -1 is energized and remains energized as long as
the blower motor BLWM is energized.
f. Heat- -Off Delay- - When the thermostat is satisfied, the
R- -to- -W circuit is opened, de- -energizing the gas valve
GV, stopping gas flow to the burners, and de- -energiz-
ing the 24- -v humidifier terminal 24VAC HUM. The
inducer motor IDM will remain energized for a 5- -sec-
ond post- -purge period. Then turn off the inducer mo-
tor 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
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 oper-
ating on the COOL speed for an additional 90 sec. Cut
jumper J2 to reduce the cooling off- -delay to 5 sec. (See
Fig. 24.)
441 01 3400 02
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 addi-
tional 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 opera-
tion.
4. Heat Pump
When installed with a heat pump, the furnace control auto-
matically changes the timing sequence to avoid long blow-
er 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 in-
ducer 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 disap-
pear, 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 Diagrams

Refer to Fig. 48 for wiring diagram.

Troubleshooting

Refer to the service label. (See Fig. 44.) The Troubleshooting
Guide (See Fig. 49) 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.
Specifications are subject to change without notice.
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