
11
Thermostat Wiring Diagrams
Y
C
Y
C
G
R
W
Y2
Y/Y1
C
G
R
W
ROOM THERMOSTAT
INTEGRATED FURNACE
CONTROL MODULE
REMOTE COOLING UNIT
(SINGLE STAGE)
Thermostat - Single-Stage Heating
with Single-Stage Cooling
Figure 3
Y1
C
Y1
C
G
R
W
Y2
Y/Y1
C
G
R
W
ROOM THERMOSTAT
INTEGRATED FURNACE
CONTROL MODULE
REMOTE COOLING UNIT
(TWO STAGE)
Y2
Y2
Thermostat - Single-Stage Heating with
Two-Stage Cooling
Figure 4
WARNING
HIGH VOLTAGE!
To avoid personal injury or death due to
electrical shock, disconnect electrical power
before servicing or changing any electrical
wiring.
Fossil Fuel Applications
This furnace can be used in conjunction with a heat pump
in a fossil fuel application. A fossil fuel application refers to
a combined gas furnace and heat pump installation which
uses an outdoor temperature sensor to determine the most
cost efficient means of heating (heat pump or gas furnace).
A heat pump thermostat is required to properly use a
single-stage furnace in conjunction with a heat pump. Refer
to the fossil fuel kit installation instructions for additional
thermostat requirements.
Strictly follow the wiring guidelines in the fossil fuel kit
installation instructions. All furnace connections must be
made to the furnace two-stage integrated control module
and the “FURNACE” terminal strip on the fossil fuel control
board.
Twinning
Two furnaces of the same model may be twinned. The
integrated control board has a 3/16” terminal labeled “TWIN”
located beside the low voltage thermostat connection strip.
Twinning allows simultaneous operation of two furnaces
and forces the indoor blower motors of each furnace to
operate synchronously into a common duct system. Using
the twinning function will require only field installed wiring
with no external kits or parts. The staging and speed tap
options must be set the same on both furnaces.
NOTE: Each furnace must be connected to it’s own 115
VAC power supply. The L1 connection to each furnace
must be in phase (connected to circuit breakers on the
same 115 VAC service panel phase leg). To verify that
the furnaces are in phase, check from L1 to L1 on each
furnace with a voltmeter. If the furnaces are in phase,
the voltage between both furnaces will be ZERO.
ROOM THERMOSTAT
Y2
Y/Y1
C
G
R
W
Y2
Y/Y1
C
G
R
W
Y2
Y/Y1
C
G
R
W
TWIN
TWIN
COND UNIT
CONTACTOR
COND UNIT
CONTACTOR
FURNACE 1
FURNACE 2
Figure 5
CAUTION
To prevent unreliable operation or equipment damage, the
gas manifold pressure must be as specified on the unit rating
plate. Only minor adjustments should be made by adjusting
the gas valve pressure regulator.
WARNING
Possible property damage, personal injury or death may
occur if the correct conversion kits are not installed. The
appropriate kits must be applied to ensure safe and proper
furnace operation. All conversions must be performed by a
qualified installer or service agency.
GAS SUPPLY AND PIPING
Natural Gas
Minimum: 4.5" w.c.
Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
INLET GAS SUPPLY PRESSURE
The furnace rating plate includes the approved furnace gas
input rating and gas types. The furnace must be equipped
to operate on the type of gas applied. This includes any
conversion kits required for alternate fuels and/or high
altitude.