Carrier 58DXT - Adaptive Heating Mode

NOTE: If power interruption occurs during "call for heat" (W/W1
or W/W1-and-W2), control starts 90-sec blower only on period 2
sec after power is restored if thermostat is still calling for gas
heating. The red LED flashes code 12 during 90-sec period, after
which LED will be on continuously as long as no faults are
detected. After 90-sec period, furnace responds to thermostat
normally.
Blower door must be installed for power to be conducted through
blower door interlock switch ILK to furnace control CPU, trans-
former TRAN, inducer motor IDM, blower motor BLWM, hot
surface ignitor HSI, and gas valve GV.
1. Adaptive Heating Mode—Single-Stage Thermostat and
2-Stage Heating
(See Fig. 11 for thermostat connections.)
NOTE: With high-heat-only switch SW-1 off, low-heat-only
switch SW-2 selects either low-heat-only operation mode when on
(see item 2 below), or adaptive heating mode when off in response
to "call for heat." (See Fig. 13.) When high-heat-only switch SW-1
is on, it always causes high-gas-heat operation when R-W/W1
circuit is closed, regardless of the setting of low-heat-only switch
SW-2.
Fig. 12—Heating and Cooling Application Diagram With 2-Stage Thermostat and 2-Stage Condensing Unit
A97444
115-V FUSED
DISCONNECT
SWITCH
(WHEN REQUIRED)
JUNCTION
BOX
CONTROL
BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-
ONLY
SEVEN
WIRE
2-STAGE THERMOSTAT TERMINALS
FIELD-SUPPLIED
FUSED DISCONNECT
2-SPEED
CONDENSING
UNIT
FURNACE
G
R

W2 Y2 G Y1 C
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
 
Y2
Y1
C
WHT
BLK
WHT
BLK
W1 R
W2
COM
W/W1
Y/Y2
NOTES: 1. Connect Y-terminal as shown for proper operation.
2. Some thermostats require a "C" terminal connection as shown.

3. If any of the original wire, as supplied, must be replaced,
use same type or equivalent wire.
Table 6—Setup Switch Description
SETUP
SWITCH NO.
NORMAL
POSITION
DESCRIPTION OF USE
SW-1
Only High-Gas Heat
OFF
(Staged Gas
Heat)
Turn switch on to obtain only
high-gas-heat operation on
any call for heat regardless of
whether R-W/W1,
or R-W/W1, -W2
is closed. SW-1 overrides
SW-2.
SW-2
Low-Gas Heat
(Adaptive Algorithm)
OFF
(Single-Stage
Thermostat)
Turn switch off for installations
with single-stage thermostats;
control selects low-gas-heat
or high-gas-heat operation
based on previous cycles.
Turn switch on for installations
with 2-stage thermostats to
permit only low-gas-heat op-
eration in response to closing
R-W/W1. High-gas heat is
supplied only when R to
W/W1 and W2 is closed.
SW-3 and
SW4
ON, OFF
Switches control gas heating
blower off delay. (See Table
7.)
Table 7—Blower Off Delay
Setup Switch Position
DESIRED HEATING
MODE BLOWER OFF
DELAY (SEC)
SETUP SWITCH
SW-3 SW-4
90 OFF OFF
135 OFF ON
180 ON OFF
225 ON ON
Fig. 13—Setup Switches on Furnace Control
(Factory Settings)
A96402
BLOWER-
OFF
DELAY
LOW
HEAT
(ADAPTIVE
ALGORITHM)
HIGH
HEAT
ONLY
43 2
OFF
ON
1
11