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Low voltage connections (24 VAC) from the thermostat
are wired to the terminal strip on the integrated control
in the furnace. Recommended minimum wire gauge for
thermostat wiring is shown in
• The thermostat should be mounted about 5 feet above
the floor on an inside wall. DO NOT install the thermostat
on an outside wall or any other location where its
operation may be adversely affected by radiant heat from
fireplaces, sunlight, or lighting fixtures, and convective
heat from warm air registers or electrical appliances.
Refer to the thermostat manufacturer's instruction sheet
for detailed mounting information.
• Depending on the type of air conditioning unit and
thermostat used, both blower applications utilize three
basic wiring configurations
Single Stage AC & Single Stage Thermostat
This option does not use the full two-stage control
capability of the furnace, but the possibility of timed
autostaging is available. See also Autostaging for Single
Stage Thermostats.
• Connect the thermostat's W output to the furnace control
boards W1 terminal. This allows the furnace to always
run in low output mode. See
• Always connect the thermostat C & R to the furnace
control board C & R.
• For cooling, connect the thermostats Y signal to the
furnace control board Y / Y2 terminal.
• Field supplied wires should also connect Y / Y2 & C to
the outdoor unit's Y & C terminals.
ROOM THERMOSTAT
(SINGLE STAGE)
W
Y
G
1 C R DHUM
A/C CONDENSING UNIT
(SINGLE STAGE)
Y/Y2
G
W1 R
Y1
W2 C
TWO STAGE FURNACE BOARD
Figure 22. Wiring Configuration 1
Single Stage AC & Two Stage Thermostat
This option uses the full two stage heating capability of the
furnace with a single stage outdoor unit. See
• Connect the thermostat's W1 & W2 outputs to the
furnace control board's W1 & W2 terminals.
• Always connect the thermostat C & R to the furnace
control board C & R
• For cooling, connect the thermostats Y signal to the
furnace control board Y / Y2 terminal.
• Field supplied wires should also connect Y / Y2 & C to
the outdoor unit's Y & C terminals.
26
Table 5 (page
25).
Figure
22.
Y
HIGH EFFICIENCY
C
BLOWER MOTOR
CONTROL BOARD
Figure
ROOM THERMOSTAT
(TWO - STAGE)
W W
Y
G 2 1 C R DHUM
Y/Y2 G
W1 R
Y1
W2 C
TWO STAGE FURNACE BOARD
Figure 23. Wiring Configuration 2
Two-Stage AC & Two-Stage Thermostat
This option uses the full two stage heating capability of
the furnace with a two stage outdoor unit. See
• Connect the thermostat's W1 & W2 outputs to the
furnace control board's W1 & W2 terminals.
• Always connect the thermostat C & R to the furnace
control board C & R.
• For cooling, connect the thermostat Y & Y1 to the furnace
control board's Y / Y2 & Y1 terminal's.
• Field supplied wires should also connect the Y / Y2 &
Y1 signals to the outdoor unit's Y & Y1 terminals.
• Connect terminal C to the outdoor unit's C.
ROOM THERMOSTAT
(TWO STAGE)
Y Y
W W
2 1 G 2 1 C R DHUM
Y/Y2 G
W1 R
Y1
W2 C
TWO STAGE FURNACE BOARD
Figure 24. Wiring Configuration 3
Autostaging for Single Stage Thermostats
The Autostaging feature makes it possible to use a single
stage thermostat and still receive some of the benefits
of 2-stage furnace operation. If Autostage is enabled,
the furnace will drop to LOW fire after initially starting in
HIGH fire. After a period of 10 minutes, the furnace will
then stage up to HIGH fire, until the heating load is met.
See
Figure 22
and the Low Voltage Connection section
on
page
25.
23.
The autostaging option is selected using the autostage
jumper located near the thermostat terminal block. See
Figure 31 (page
39). When the autostage jumper is
moved from OFF to ON, the following occurs during a
call for heat:
Setting the Autostage jumper in the ON position signals
the control to utilize a 10 minute delay between LOW fire
and HIGH fire when a call for heat is supplied via 24V
signal to W1. This setting is the same as jumping R to W2.
Y
HIGH EFFICIENCY
C
BLOWER MOTOR
CONTROL BOARD
A/C CONDENSING UNIT
(SINGLE STAGE)
Figure
Y2
HIGH EFFICIENCY
Y1
BLOWER MOTOR
C
CONTROL BOARD
A/C CONDENSING UNIT
(TWO STAGE)
24.
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