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DIPSWITCHES
Cooling/Heat Pump Airflow Trim; SW6 & SW7
Two dipswitches (SW6, SW7) are provided for legacy cool
airflow trim. The value used for each selection is specified
below.
Selections are as follows:
Selection
SW6
A
OFF
B
ON
C
OFF
D
ON
*Factory Setting
ODD (On Demand Dehumidification); SW8
One dipswitch (SW8) is provided to enable the dehumidifi-
cation feature in legacy mode. Selections are as follows:
SW8=OFF
ODD not enabled. (Factory Setting)
SW8=ON
ODD enabled. 0VAC on "HUM STAT" will
decrease airflow in cooling.
Tandem Airflow Select; SW9
One dipswitch (SW9) is provided to select the percentage
of airflow for the base first stage cooling airflow in legacy
mode. Note that further adjustments may also be applied
(e.g. for active dehumidification or cooling airflow trim).
nd
SW9
% of 2
SW9=ON
50%
SW9=OFF*
Value from dipswitches SW4 & SW5
(see above).
*Factory Setting
Auto Stage; SW10 & SW11
Two dipswitches are provided to either run the furnace in
the single rate mode or to select between modulating,
timed staging or strictly two-stage operation. Refer to the
chart below for an overview of operation based on the dif-
ferent combinations of these two dipswitches.
OFF/OFF- NORMAL OPERATION – MODULATING OR
TIMED STAGING HEAT
When both Mode dipswitches are set to the "OFF" posi-
tion, the furnace operates as normal to a legacy modulat-
ing heat call ("W1" with PWM signal on "V/W2") with the
firing rate adjusted by the PWM signal. The furnace oper-
ates in timed staging mode when responding to a low heat
call (24 VAC present on "W1" and no signal present on
"V/W2"). A call for low heat alone will start the heating se-
quence as normal and output the low heat rate (40% heat)
for a period of ten minutes followed by a transition to a
65% heating rate. The 65% heating rate will remain active
for the next ten minutes and will be followed by maximum
heat (100% heat) for the remainder of the heating call.
Once the control has switched to high stage heat through
the staging method, the remainder of the heat call will take
place at 100% heat even if a signal somehow becomes
present on "V/W2". The switch to 65% fire after ten min-
74
SW7
Description
OFF
No Cooling Adjust.*
OFF
+10%
ON
-10%
ON
No Cooling Adjust.
stage cooling airflow
One dipswitch (SW8) is provided to enable the dehumidification feature in legacy mode. Selections are
as follows:
SW8=OFF
ODD not enabled. (Factory Setting)
SW8=ON
ODD enabled. 0VAC on "HUM STAT" will decrease airflow in cooling.
Tandem Airflow Select; SW9
One dipswitch (SW9) is provided to select the percentage of airflow for the base first stage cooling
airflow in legacy mode. Note that further adjustments may also be applied (e.g. for active
dehumidification or cooling airflow trim).
nd
SW9
% of 2
stage cooling airflow
ON
50%
OFF
Value from dipswitches SW4 & SW5 (see above).
Auto Stage; SW10 & SW11
Two dipswitches are provided to either run the furnace in the single rate mode or to select between
modulating, timed staging or strictly two-stage operation. Refer to the chart below for an overview of
operation based on the different combinations of these two dipswitches.
MODE
SW10
Modulating / Timed Staging
OFF
40% single rate
ON
100% single rate
OFF
Two-Stage
ON
OFF/OFF - NORMAL OPERATION – MODULATING OR TIMED STAGING HEAT
utes and high fire (100% heat) after a total of twenty min-
When both Mode dipswitches are set to the "OFF" position, the furnace operates as normal to a legacy
utes into the heat call will occur as long as there is no 24
modulating heat call ("W1" with PWM signal on "V/W2") with the firing rate adjusted by the PWM
VAC signal present at "V/W2".
signal. The furnace operates in timed staging mode when responding to a low heat call (24 VAC present
on "W1" and no signal present on "V/W2"). A call for low heat alone will start the heating sequence as
If 24VAC is sensed on "V/W2", 100% heating operation
normal and output the low heat rate (40% heat) for a period of ten minutes followed by a transition to a
will take place and the timed staging algorithm will be can-
65% heating rate. The 65% heating rate will remain active for the next ten minutes and will be followed
by maximum heat (100% heat) for the remainder of the heating call. Once the control has switched to
celled until the end of current heat call as it is assumed
high stage heat through the staging method, the remainder of the heat call will take place at 100% heat
that the customer wants to operate the furnace as a two-
even if a signal somehow becomes present on "V/W2". The switch to 65% fire after ten minutes and
stage furnace with no timed staging. When the "V/W2" ter-
minal becomes inactive while the "W1" request remains
active, the IFC will switch to the low heat rate (40%). If the
unit is already operating at 100% heat rate due to the
timed staging algorithm then the IFC will continue to run at
100% heat rate for the rest of the heat cycle regardless of
whether 24VAC is applied to or removed from "V/W2".
If a PWM signal is sensed at terminal "V/W2", the timed
staging feature will be cancelled until the end of current
heat call and normal modulating heat will take place as ac-
cording to Section, item #3. If the unit is already operating
at 100% heat rate due to the timed staging algorithm, then
the IFC will continue to run at 100% heat rate for the rest
of the heat cycle regardless of the PWM signal applied to
the "V/W2" terminal.
Control must be able to sense a change in PWM signal in
no more than 3 seconds.
ON/OFF- LOW HEAT SINGLE RATE MODE
For the single rate mode, when SW10 is "ON" and SW11
is "OFF", the furnace will operate in the 40% heat mode
with any legacy call for heat (first stage, second stage or
modulating). A legacy heat call will cause the furnace to go
through a normal heating cycle with heating fire rate fixed
at 40%. The voltage at the terminal labeled "V/W2" will be
ignored.
OFF/ON- HIGH HEAT SINGLE RATE MODE
When SW10 is "OFF" and SW11 is "ON", the furnace will
operate in the 100% heat mode with any legacy call for
heat (first stage, second stage or modulating). That is, a
24 VAC signal on "W1" will cause the furnace to go
through a normal heating cycle with heating fire rate fixed
at 100%. The voltage at the terminal labeled "V/W2" will
be ignored.
ON/ON - RESPONSE TO TWO-STAGE THERMOSTAT
WITH 3 STAGES OF HEAT OPERATION
When both Mode dipswitches are set to the "ON" position,
a 24VAC signal present on "W1" with no signal on "V/W2"
will always operate low-fire heat (40% heat rate). With
24VAC present on both "W1" & "V/W2" the IFC will oper-
ate at 65% gas heat for ten minutes followed by 100%
heat until 24 VAC is no longer present on "V/W2". This se-
quence will be triggered also when 24VAC signal on
"V/W2" appears during "W1" operation.
SW11
OFF
(Factory Setting)
OFF
ON
ON
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