24
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 34
R
Y
C
Furnace
Integrated
Control
Module
Remote Condensing Unit
(Single-Stage Cooling)
R
Thermostat - Two-Stage Heating with Single-Stage Cooling
Figure 35
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
Figure 36
Thermostat Wiring Diagrams
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
stepping up can be set at either a fixed 10 or 20 minute
time delay or a load based variable time between 1 and
12 minutes (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
1
2
3
4
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
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 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).
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
installation 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.
Twinning
Using the “TWIN” terminals and proper wiring enables
two *MEC96 furnaces of the same model and size to be
twinned. Twinning allows simultaneous operation of two
furnaces and forces the indoor blower motors of each
furnace to operate synchronously into a common duct
system. Using the twinning function will require only field
installed wiring with no external kits or parts.
•
· The staging DIP switches and speed tap DIP switches
must be set the same on both furnaces.
•
NOTE:
Each furnace must be connected to it’s
own 115 VAC power supply. The L1 connection to
each furnace must be in phase (connected to circuit
breakers on the same 115 VAC service panel phase
leg). To verify that the furnaces are in phase, check
from L1 to L1 on each furnace with a voltmeter. If
the furnaces are in phase, the voltage between both
furnaces will be
ZERO.
Содержание *MEC96
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