S9V2-VS-SVX001-1C-EN
115
5. After the ignitor warm up, the 1
st
stage gas valve
relay is closed, energizing the 1
st
stage gas valve
solenoid to allow ignition.
6. The first burner will ignite and flame will crossover
to the remaining burners, establishing current to
the flame sensor. Flame sensing must take place
within 4 seconds.
7. Once flame sense has been achieved, a timer on the
IFC starts and after the “Blower On” delay has
completed, the indoor blower will energize and run
at the 1
st
stage gas heating speed.
• During this time, the variable speed inducer will
start its 1
st
stage learning routine, seen as LLRR11
on the seven segment LED display. XXtt11 and LLRR11
will alternately be displayed until the learning
routine has been successfully completed. See
Learning Routine section below for specifics.
8. Once the 1
st
stage learning routine has successfully
been achieved, the seven segment LED will
alternately read:
XtI = Gas heating, Stage 1
ARF = Airflow
060 = 600 calculated cfm (value shown x 10)
9. R-W2 contacts close on the thermostat sending
24VAC to the W2 low voltage terminal of the IFC.
Technician should read 24VAC from W2 to B/C. The
seven segment LED will read “HT2”.
10. The IFC checks to insure that PS2 is open and the
inducer is ramped up to the predetermined factory
default 2
nd
stage speed, closing PS2 pressure
switch. The second stage gas valve relay on the IFC
closes, energizing second stage gas valve. The
indoor blower motor will ramp up to the 2
nd
stage
gas heating speed.
• During this time, the variable speed inducer will
start its 2
nd
stage learning routine, seen as LLRR22
on the seven segment LED display. HHTT22 and LLRR22
will alternately be displayed until the learning
routine has been successfully completed. See
Learning Routine section below for specifics
11. Once the the 2
nd
stage learning routine has
successfully been completed, the seven segment
LED will alternately read:
HT2 = Gas heating, Stage 2
ARF = Airflow
123 = 1230 calculated cfm (value shown x 10)
12. When the temperature raises enough to satisfy the
thermostat setting, contacts R-W2 will open, 2
nd
stage gas valve will close, the indoor blower motor
will ramp down to 1
st
stage, and the unit will
continue to run until R-W1 contacts open.
13. When the temperature raises enough to satisfy the
thermostat setting, contacts R-W1 will open.
14. The gas valve relay will open, closing the gas valve.
The inducer will continue to run for approximately 5
seconds to remove any combustion byproducts
from inside the furnace.
15. The indoor blower continues to run to remove heat
from the heat exchangers. This blower off time is
field adjustable through the IFC menu setup option.
The seven segment LED will read “IDL” = Idle, no
thermostat demand.
SSiinnggllee SSttaaggee CCoooolliinngg
1. R-Y1-G contacts on the thermostat close sending
24VAC to the Y1 and G low voltage terminals on the
IFC. Technician should read 24VAC between Y1-B/C
and between G-B/C.
NNoottee:: Factory supplied Y1-O jumper must remain in
place for proper seven segment LED readout.
If removed, seven segment LED will read
“
HP1
”.
2. 24VAC is sent to the OD unit via thermostat wiring.
3. The indoor blower ramps to the cooling airflow.
The seven segment LED for example will alternately
read:
CL1 = Cooling, Stage 1
ARF = Airflow
080 = 800 calculated cfm (value shown x 10)
4. When the temperature is lowered enough to satisfy
the thermostat setting, contacts R-Y1-G will open.
5. The OD unit shuts off and the indoor blower shuts
off, unless a blower off delay has been enabled in
the IFC setup menu options. The seven segment
LED will read “IDL” = Idle, no thermostat demand.
TTwwoo SSttaaggee CCoooolliinngg
1. R-Y1-G contacts on the thermostat close sending
24VAC to the Y1 and G low voltage terminals on the
IFC. Technician should read 24VAC between Y1-B/C
and between G-B/C.
NNoottee:: Factory supplied Y1-O jumper must remain in
place for proper seven segment LED readout. If
removed, seven segment LED will read “
HP1
”.
2. 24VAC is sent to the OD unit via thermostat wiring.
3. The indoor blower ramps to the cooling airflow.
The seven segment LED for example will alternately
read:
CL1 = Cooling, Stage 1
ARF = Airflow
080 = 800 calculated cfm (value shown x 10)
4. R-Y2 contact on the thermostat closes sending
24VAC to Y2 low voltage terminal on the IFC.
Technician should read 24VAC between Y2 and B/C.
5. 24VAC is sent to the OD unit via thermostat wiring.
6. The indoor airflow ramps to 2
nd
stage cooling
airflow. The seven segment LED for example will
read:
CL2 = Cooling, Stage 2
ARF = Airflow
160 = 1600 calculated cfm (value shown x 10)
SSeeqquueennccee ooff OOppeerraattiioonn
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