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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 Table 5 (page 25).
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 & Sin_ge
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 Wl terminal. This allows the furnace to always
run in low output mode. See (Figure 24)
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.
i
ROOM THERMOSTAT
i
SINGLE STAGE)
ITI IWloI ID,"UM
I
I
I I
I
I
I I
I
I
I I
U
I
I
IFI- ......
I
I
III
I
I
III
I
I
III
A/C CONDENSING
UNIT
I
I
III
I
I
I1 J
(SINGLE STAGE)
I
I
III
l
_'
I
I
II
Y1
W2
C
TWO
STAGE
FURNACE
BOARD
HIGH EFFICIENCY
BLOWER
MOTOR
CONTROL
BOARD
Figure 24. 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 Figure 22.
Connect the thermostat's
Wl
& W2 outputs to the
furnace control board's Wl & 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.
ROOM
THERMOSTAT
"1
(TWO-
STAGE)
|
i
i
i
i
i
i
i
I
I
I
I
I
1
I
I
I
I
1
I
i
I
r----7
i
i
i
- "f - "[
_-
HIGH
EFFICIENCY
U
I
.....
BLOWER
MOTOR
, ',
r, _ -
CONTROL
BOARD
I
I
II
I
I
I I
A/C
CONDENSING
UNIT
I
I
EI
(SINGLE
STAGE)
I
I
II
I
I
II
I
I
/i
I
I
,', ,!dM'Nr,!M
I
I IIll
Y/Y2
G
Wl
R
Y1
W2
C
TWO
STAGE
FURNACE
BOARD
Figure 25. 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 Figure 26.
Connect the thermostat's
Wl
& W2 outputs to the
furnace control board's Wl & 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
1
(TWO STAGE)
I_
_
A/C CONDENSING
UNIT
I I
(TWO STAGE)
ii
i I
I/1/I
Iii
l
Y
Y1
W2
C
TWO STAGE FURNACE
BOARD
HIGH EFFICIENCY
BLOWER
MOTOR
CONTROL
BOARD
Figure 26. Wiring Configuration
3
Autostaging
for Single
Stage Thermostats
The Autostaging
feature
included on all G7 2-stage
furnaces 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 time (8 or 12 minutes) the furnace will then stage up
to HIGH fire, until the heating load is met. See Figure 24
and the Low Voltage Wiring section (page 25).
Autostaging
options are selected
using the autostage
jumper located near the thermostat terminal block. See
Figure 32 ( page 40).When the autostage jumper is moved
from NONE to SHORT or LONG, the following occurs
during a call for heat:
26
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