47
In continuous fan mode, the CTK0* thermostat provides
the airflow demand. The thermostat may be configured
for one of three continuous fan speed settings allow for
25%, 50% or 75% airflow, based on the furnaces’ maximum
airflow capability. During continuous fan operation, the
thermostat sends a fan request along with the continuous
fan demand to the furnace. The furnace, in turn, sends
the demand to the ECM motor. The ECM motor delivers
the requested continuous fan airflow. The control board
also has the capability of providing constant fan by supply-
ing 24 VAC input to G terminal while using a communicat-
ing thermostat (CTK0*). This will allow the furnace fan to
support ERV/HRV and other accessories while using a
communicating thermostat. The continuous fan speed can
be adjusted on switch bank S5, DIP switch 3 & 4. Connec-
tion to the G terminal can be made by using two four pin
terminal blocks (similar to using a Y1 input) or by using the
9 pin connector that ships on the control board. Remove
the red keying tabs from the on-board connector block to
use either method.
F
OSSIL
F
UEL
A
PPLICATIONS
This furnace can be used in conjunction with a ComfortNet™
compatible 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). The balance point temperature may
be adjusted via the CTK0* thermostat advanced user menus
(see CTK0* instructions for additional information).
CTK0* W
IRING
NOTE:
Refer to Electrical Connections for 115 volt line connections
to the furnace.
NOTE:
A removable plug connector is provided with the
control to make thermostat wire connections. This plug may
be removed, wire connections made to the plug, and replaced.
It is
strongly
recommended that multiple wires into a single
terminal be twisted together prior to inserting into the plug
connector. Failure to do so may result in intermittent operation.
Typical 18 AWG thermostat wire may be used to wire the
system components. One hundred (100) feet is the maximum
length of wire between indoor unit and outdoor unit, or be-
tween indoor unit and thermostat. Wire runs over (100)
feet require larger gauge wire.
F
OUR
-W
IRE
I
NDOOR
AND
O
UTDOOR
W
IRING
Typical ComfortNet™ wiring will consist of four wires be-
tween the indoor unit and outdoor unit and between the in-
door unit and thermostat. The required wires are: (a) data
lines, 1 and 2; (b) thermostat “R” (24 VAC hot) and “C” (24
VAC common).
T
WO
-W
IRE
O
UTDOOR
, F
OUR
-W
IRE
I
NDOOR
W
IRING
As few as two wires can be utilized between the indoor and
outdoor units. For this wiring scheme, only the data lines, 1 and
2, are needed between the indoor and outdoor units. A 40VA,
208/230 VAC to 24VAC transformer must be installed in the out-
door unit to provide 24VAC power to the outdoor unit’s electronic
control. The transformer is included in selected communicat-
ing thermostat kits. See kit instructions for mounting and wir-
ing instructions. Four wires are required between the indoor
unit and thermostat. If using a communicating thermostat
kit that does not include a transformer in a dual fuel system,
the accessory transformer kit TFK01 should be used.
NOTE:
Use of the accessory transformer is recommended if
installing a dual fuel/fossil fuel system. Failure to use the
transformer in the outdoor unit could result in over loading of
the furnace transformer.
C
OMFORT
N
ET
™ C
OMPATIBLE
F
URNACE
WITH
N
ON
-C
OMFORT
N
ET
COMPATIBLE
S
INGLE
-S
TAGE
A
IR
C
ONDITIONER
Four wires are required between the furnace and thermostat.
Two wires are required between the furnace control and single
stage air conditioner. For this system configuration, the “Y1”
terminal on the integrated furnace control becomes an output
rather than an input. The “Y1” connection to the outdoor
unit is made using both of the 4-position thermostat connec-
tors in the CTK0* kit. Remove the red keying tabs from the
on-board connector block and position both 4-position con-
nector such that “1”, “2”, “R”, “C”, and “Y1” positions are
filled.
C
OMFORT
N
ET
™ S
YSTEM
A
DVANCED
F
EATURES
The ComfortNet system permits access to additional system in-
formation, advanced setup features, and advanced diagnostic/
troubleshooting features. These advanced features are orga-
nized into a menu structure. The menus are accessed and navi-
gated as described in the instructions provided with the com-
municating control.
A 24 VAC input may be applied to the G terminal of the modu-
lating furnace control board to operate the indoor blower to
support and HRV/ERV. The 24 VAC source must originate from
the R terminal of furnace.
W1 W2 Y1
Y2
O
DEHUM
24 vac "G" input to Furnace
Integrated Control module From
ERV / HRV or Similar Devices
1
1
2
R
C
2
Furnace Integrated
Control Module
R
C
G
CTK0* Thermostat
4-Pin (X2), 7 Pin, or 9 Pin Connector
Diagram 1
