Installation Instructions

25
24 VOLT THERMOSTAT WIRING
W IRE ROUTING MUST NOT INTERFERE WITH CIRCULATOR BLOWER
OPERATION , FILTER REMOVAL OR ROUTINE MAINTENANCE .
IMPORTANT NOTE
Low voltage connections can be made through either the right or
left side panel. Thermostat wiring entrance holes are located in
the blower compartment. The following figure shows connec-
tions for a “heat/cool system”.
This furnace is equipped with a 40 VA transformer to facilitate
use with most cooling equipment. Consult the wiring diagram,
located on the blower compartment door, for further details of
115 Volt and 24 Volt wiring.
R
Y C
Furnace
Integrated
Control
Module
Remote Condensing Unit
(Single-Stage Cooling)
R
Thermostat - Single -Stage Heating with Single-Stage Cooling
NOTE: To apply a single-stage Heating Thermostat, the thermostat
selector switch on the Integrated Control Module must be set
on single-stage.
Figure 30
R
Y C
Furnace
Integrated
Control
Module
Remote Condensing Unit
(Single-Stage Cooling)
R
Thermostat - Two-Stage Heating with Single-Stage Cooling
Figure 31
W1 W2
Y
Furnace
Integrated
Control
Module
Remote Condensing Unit
(Two-Stage Cooling)
Y2
W1 W2
Y2
Thermostat - Two-Stage Heating with Two-Stage Cooling
Thermostat Wiring Diagrams
Figure 32
SINGLE-STAGE HEATING THERMOSTAT APPLICATION
A single-stage thermostat with only one heating stage may
be used to control this furnace. The application of a single-
stage thermostat offers a timed transition from low to high
fire. The furnace will run on low stage for a fixed period of
time before stepping up to high stage to satisfy the
thermostat’s call for heat. The delay period prior to step-
ping up can be set at either a fixed 10 or 20 minute time
delay or a load based variable time between 1 and 12 min-
utes (AUTO mode). If the AUTO mode is selected, the control
averages the cycle times of the previous three cycles and
uses the average to determine the time to transition from
low stage to high stage.
PCBBF139 CONTROL BOARD
1234
2 Stage Stat OFF OFF
1 Stg Stat 10 min delay ON OFF
1 Stg Stat 20 min delay ON ON
Auto OFF* ON*
90 OFF OFF
120 OFF ON
150 ON* OFF*
180 ON ON
* FACTORY
SETTING
Dip Switch
Switch
Group
Function
S3
S3
Heating Fan
Off Delay
Purpose
Thermostat
Setup
PCBBF137 CONTROL BOARD
DIP
Switch
Group
DIP
Switch
Number
Purpose
Auto 1 OFF* 2 ON*
10 Minutes 1 ON 2 OFF
20 Minutes 1 ON 2 ON
2 Stage 1 OFF 2 OFF
90 Seconds 3 OFF 4 OFF
120 Seconds 3 OFF 4 ON
150 Seconds 3 ON* 4 OFF*
180 Seconds 3 ON* 4 ON
* = Factory Position
Function
S1
1, 2
3, 4
Heat
Staging /
Delay
Blower
Heat Off
Delay
FOSSIL FUEL APPLICATIONS
This furnace can be used in conjunction with a heat pump in a
fossil fuel application. A fossil fuel application refers to a com-
bined gas furnace and heat pump installation which uses an out-
door temperature sensor to determine the most cost efficient
means of heating (heat pump or gas furnace).
A heat pump thermostat with three stages of heat is required to
properly use a two-stage furnace in conjunction with a heat pump.
Refer to the fossil fuel kit installation instructions for additional
thermostat requirements.
Strictly follow the wiring guidelines in the fossil fuel kit installa-
tion instructions. All furnace connections must be made to the
furnace two-stage integrated control module and the “FURNACE”
terminal strip on the fossil fuel control board.