Trane S9V2B040U3VSAE Installation, Operation And Maintenance Manual page 117

7. When the temperature is lowered enough to satisfy
the thermostat setting, contacts R-Y1-Y2-G will
open.
8. 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.
V V a a r r i i a a b b l l e e S S p p e e e e d d I I n n d d u u c c e e r r L L e e a a r r n n i i n n g g R R o o u u t t i i n n e e
The purpose of the learning routine is to determine the
most efficient inducer operating speed for the furnace
in a given heat stage. On a call for gas heat, or
transition to a given gas heat stage, the inducer is
commanded to a speed in order to close the pressure
switch for that stage.
N N o o t t e e : : NOTE: Gas manifold measurements or
adjustments must not be made until the learning
routine for each stage has been successfully
completed.
There are two learning routines, one for 1
nd
heat and another for 2
routine is separate and will occur:
1. Upon initial commissioning of the furnace
2. When power to the furnace has been interrupted
3. After the below number of heating cycles has been
reached
st
a. 150 1 stage cycles
nd
b. 100 2 stage cycles
s s t t
1 1 S S t t a a g g e e H H e e a a t t
st
1. When 1 stage gas heat is requested, the variable
speed inducer is energized and will run at the
predetermined factory default 1
speed. Once the ignition process and the blower on
delay have successfully completed the IFC will
begin the Inducer Learning Routine as outlined
below
P P S S 1 1 c c l l o o s s e e s s a a t t d d e e f f a a u u l l t t s s p p e e e e d d
a. The inducer speed is reduced every 2 seconds
until PS1 opens
b. At the time PS1 opens, the IFC stores the
inducer RPM
S9V2-VS-SVX001-1B-EN
st
stage gas
stage gas heat. Each learning
st
stage inducer
c. The inducer RPM is then raised every 3 seconds
to re-close PS1. Upon PS1 closing, the IFC has
now learned the most efficient inducer speed for
st
1 stage gas heat operation.
P P S S 1 1 d d o o e e s s n n o o t t c c l l o o s s e e a a t t d d e e f f a a u u l l t t s s p p e e e e d d
The IFC will increase the speed of the inducer until:
a. The maximum RPM for 1
reached
b. Or PS1 closes
Once PS1 closes, the learning routine will begin
as stated above.
n n d d
2 2 S S t t a a g g e e H H e e a a t t
nd
1. When 2 stage gas heat is requested, the variable
speed inducer will run at the predetermined factory
nd
default 2 stage inducer speed.
P P S S 2 2 c c l l o o s s e e s s a a t t d d e e f f a a u u l l t t s s p p e e e e d d
a. The inducer speed is reduced every 2 seconds
until PS2 opens
b. At the time PS2 opens, the IFC stores the
inducer RPM
c. The inducer RPM is then raised every 3 seconds
to re-close PS2. Upon PS2 closing, the IFC has
now learned the most efficient inducer speed for
nd
2 stage gas heat operation.
P P S S 2 2 d d o o e e s s n n o o t t c c l l o o s s e e a a t t d d e e f f a a u u l l t t s s p p e e e e d d
The IFC will increase the speed of the inducer until:
a. The maximum RPM for 2
reached
b. Or PS2 closes
Once PS2 closes, the learning routine will begin
as stated above. If PS2 does not close after
reaching the maximum RPM, a PS2 open error
will be reported and the furnace will continue to
st
run in 1 stage for 10 minutes and retry 2
stage. This process will repeat until the request
nd
for 2 stage heat is removed.
S S e e q q u u e e n n c c e e o o f f O O p p e e r r a a t t i i o o n n
st
stage gas heat is
nd
stage gas heat is
nd
117