5
1. Disconnect all power to the furnace. Do not touch the integrated control module or any wire connected to the control prior to
discharging your body’s electrostatic charge to ground.
2. Firmly touch a clean, unpainted, metal surface of the furnaces near the control. Any tools held in a person’s hand during
grounding will be discharged.
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 adhered to,
including but not limited to: unit maximum external static pres-
sure, gas pressures, BTU input rating, proper electrical connections,
circulating air temperature rise, minimum or maximum CFM, and
motor speed connections.
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 automatic airflow configuration, enhanced setup fea-
tures, 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 thermostat and a non-ComfortNet compatible single stage air conditioning 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 negative pressure created by the draft inducer. The furnace control board
receives commands from the room thermostat. 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 frequency 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
Figure 1
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
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