6
3. Service integrated control module or connecting wiring
following the discharge process in step 2. Use caution
not to recharge your body with static electricity; (i.e.,
do not move or shuffle your feet, do not touch
ungrounded objects, etc.). If you come in contact with
an ungrounded object, repeat step 2 before touching
control or wires.
4. Discharge your body to ground before removing a new
control from its container. Follow steps 1 through 3 if
installing the control on a furnace. Return any old or
new controls to their containers before touching any
ungrounded object.
T
O
T
HE
I
NSTALLER
Before installing this unit, please read this manual thoroughly
to familiarize yourself with specific items which must be ad-
hered to, including but not limited to: unit maximum external
static pressure, gas pressures, BTU input rating, proper elec-
trical connections, circulating air temperature rise, minimum
or maximum CFM, and motor speed connections.
T
O
PREVENT
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
DUE
TO
FIRE
,
DO
NOT
INSTALL
THIS
FURNACE
IN
A
MOBILE
HOME
,
TRAILER
,
OR
RECREATIONAL
VEHICLE
.
WARNING
P
RODUCT
D
ESCRIPTION
F
EATURES
This furnace is a part of the ComfortNet™ family of products.
The CTK family of thermostat kits allow this furnace to be
installed as part of a digitally communicating system. The
ComfortNet system provides advanced airflow configuration,
enhanced setup features, and enhanced diagnostics. It also
reduces the number of thermostat wires to a maximum of
four. It may be also installed as part of a non-communicating
system using a standard 24 VAC thermostat.
This product may be installed with the ComfortNet thermo-
stat and a non-ComfortNet compatible single stage air condi-
tioning unit. However, this reduces the benefits of the
ComfortNet system as the enhancements will only apply to
the furnace.
The modulating furnace operation is based off of nega-
tive pressure created by the draft inducer. The furnace
control board receives commands from the room ther-
mostat. The furnace control board then controls the RPM
of the (3 phase) inducer by varying the frequency and
voltage to the inducer. This is known as variable fre-
quency drive (VFD). The inducer, pressure switches, and
gas valve are linked by pneumatic tubing. The gas valve
modulates based on this negative pressure.
5
9
4
3
12
16
28
32
11
14
15
30
17
18
2
19
21
27
24
25
20
23
26
20
22
13
30
29
31
1
6
7
7
8
8
8
Both Sides
10
UPFLOW / HORIZONTAL MODEL
Figure 1
2
5
6
9
10
11
3
12
13
16
18
19
20
23
25
26
27
21
20
31
32
7
7
8
8
8
8
8
8
4
2
17
15
1
COUNTERFLOW/HORIZONTAL
Figure 2