15
3. Models that have the junction box located in the burner
compartment will need to move the junction box directly
over.
4. Attach the junction box to the left side of the furnace, using
the screws removed in step 2.
5. Check the location of the wiring. Confirm that it will not be
damaged by heat from the burners or by the rotation of the
fan. Also confirm that wiring location will not interfere
with filter removal or other maintenance.
After the junction box is in the desired location, use washers to
connect field-supplied conduit to the junction box in accordance
with NEC and local codes. Connect hot, neutral, and ground wires
as shown in the furnace wiring diagram. The wires and ground
screw are located in the furnace junction box.
NOTE:
In downflow applications the power leads should be routed
through the supplied wire tabs when rotating junction box to the
left side.
Low voltage wires may be connected to the terminal strip.
IMPORTANT NOTE:
To avoid possible equipment malfunction, route
the low voltage wires to avoid interference with filter removal or
other maintenance.
HIGH VOLTAGE !
T
O
AVOID
THE
RISK
OF
INJURY
,
ELECTRICAL
SHOCK
OR
DEATH
,
THE
FURNACE
MUST
BE
ELECTRICALLY
GROUNDED
IN
ACCORDANCE
WITH
LOCAL
CODES
OR
IN
THEIR
ABSENCE
,
WITH
THE
LATEST
EDITION
OF
THE
N
ATIONAL
E
LECTRIC
C
ODE
.
WARNING
To ensure proper unit grounding, the ground wire should run from
the furnace ground screw located inside the furnace junction box
all the way back to the electrical panel.
NOTE:
Do not use gas
piping as an electrical ground. To confirm proper unit grounding,
turn off the electrical power and perform the following check.
1. Measure resistance between the neutral (white) connection
and one of the burners.
2. Resistance should measure 10 ohms or less.
This furnace is equipped with a blower door interlock switch which
interrupts unit voltage when the blower door is opened for servic-
ing. Do not defeat this switch.
24 V
OLT
T
HERMOSTAT
W
IRING
NOTE:
Wire routing must not interfere with circulator blower
operation, filter removal, or routine maintenance.
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 connections
for a “heat only” system and “heat/cool system”.
Furnace
Control
Furnace
Control
Remote
Condensing
Unit
Heating
Room
Thermostat
Heating/Cooling
Room Thermostat
W
W
Typical Field Wiring (24 VAC Control Circuit)
This furnace is equipped with a 40 VA transformer to facilitate use
with most cooling equipment. Consult the wiring diagram, lo-
cated on the blower compartment door, for further details of 115
Volt and 24 Volt wiring.
A single-stage thermostat with only one heating stage can be used
to control this furnace.
GME8 & AMEH8 F
URNACES
WITH
2-S
TAGE
C
ONDENSER
F
IELD
W
IRING
The GME8 and AMEH8 model furnaces may be used with a 2-stage
outdoor air conditioner. A two stage cooling/single stage gas heat
thermostat is required, in addition to a field supplied relay. The
relay must have a 24VAC coil and contacts rated for up to 1 horse
power at 125VAC.
1. Install the field supplied relay on the control mounting panel
near the furnace ignition control. The relay should be in-
stalled such that the motor leads will reach the relay contact
terminals.
2. Connect the “Y2” (high stage cool) thermostat terminal to one
coil terminal of the field supplied relay. Connect the other
field supplied relay coil terminal to the “C” terminal on the
furnace ignition control. Typical 18AWG thermostat wire may
be used.
3. Connect the common terminal of the field supplied relay to the
“LINE-H” terminal on the furnace ignition control. Use wiring
having copper conductors only and a temperature rating of at
least 105°C.
4. Using the GME8 airflow tables in this manual, determine the
motor speed tap needed to deliver the required high stage
cooling airflow. Connect the selected motor speed tap to the
normally open terminal on the field supplied relay. Use wiring
having copper conductors only and a temperature rating of at
least 105°C.
5. See the wiring schematic below.
