GMES8 GCES8 Installation Instructions
17
24 VOLT THERM OSTAT 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
Heatin
g
Room
Thermostat
Heating/Cooling
Room Thermostat
WW
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,
located 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.
SETTING THE HEAT ANTICIPATOR
The heat anticipator in older, non electronic room thermostats
must be adjusted correctly to obtain the proper number of cycles
per hour and to prevent “overshooting” the setting. Set the heat
anticipator setting to 0.7 amps. Follow the thermostat
manufacturer’s instructions on how to adjust the heat anticipa-
tor.
115 VOLT LINE CONNECTION OF ACCESSORIES
HIGH VOLTAGE !
T
O
AVOID
PERSONAL
INJURY
OR
DEATH
DUE
TO
ELECTRICAL
SHOCK
,
DISCONNECT
ELECTRICAL
POW ER
BEFORE
SERVICING
OR
CHANGING
ANY
ELECTRICAL
W IRING
.
WARNING
The furnace integrated control module is equipped with line volt-
age accessory terminals for controlling power to an optional field-
supplied electronic air cleaner.
The accessory load specifications are as follows:
Electronic Air Cleaner 1.0 Amp maximum at 120 VAC
Turn OFF power to the furnace before installing any accessories.
Follow the air cleaner manufacturers’ instructions for locating,
mounting, grounding, and controlling these accessories. Acces-
sory wiring connections are to be made through the 1/4" quick
connect terminals provided on the furnace integrated control
module. The electronic air cleaner hot terminal is identified as
EAC-H and the neutral terminal is identified as NEUTRAL. All field
wiring must conform to applicable codes. Connections should
be made as shown in the following illustration.
EAC-H
Line
Transformer
Line
Transformer
EAC
Air Cleaner
Control Module
Hot 120 VAC
Neutral 120 VAC
Optional
Accessories
If it is necessary for the installer to supply additional line voltage
wiring to the inside of the furnace, the wiring must conform to
all local codes, and have a minimum temperature rating of 105°C.
All line voltage wire splices must be made inside the furnace junc-
tion box.
The integrated control module electronic air cleaner terminals
(EAC) are energized with 115 volts whenever the circulator blower
is energized.
24 VAC HUM IDIFIER
The yellow wire connected to the I.D. Blower pressure switch is
powered anytime the pressure switch is closed and provides 24
VAC humidifier control. Remove the yellow wire and connect a
field supplied jumper wire with a “piggyback” terminal to the
pressure switch terminal. Reconnect the yellow wire to the “ piggy-
back” terminal on the jumper wire and then connect the 24 VAC
line of the humidifier to the stripped end of the jumper wire. Using
a wire nut or a field-supplied quick connect terminal can make
this connection. The wiring must conform to all local and national
codes. Connect the COM side of the humidifier to the C terminal on
the furnace control board (or to the COM side of the 24 VAC trans-
former). DO NOT CONNECT 115V HUM IDIFIER TO THESE TERM I-
NALS.
G
AS
S
UPPLY
AND
P
IPING
The furnace rating plate includes the approved furnace gas input
rating and gas types. The furnace must be equipped to operate on
the type of gas applied. This includes any conversion kits re-
quired for alternate fuels and/ or high altitude.
CAUTION
T
O
PREVENT
UNRELIABLE
OPERATION
OR
EQUIPM ENT
DAM AGE
,
THE
INLET
GAS
SUPPLY
PRESSURE
M UST
BE
AS
SPECIFIED
ON
THE
UNIT
RATING
PLATE
W ITH
ALL
OTHER
HOUSEHOLD
GAS
FIRED
APPLIANCES
OPERATING
.
Inlet gas supply pressures must be maintained within the ranges
specified in the following table. The supply pressure must be
constant and available with all other household gas fired appli-
ances operating. The minimum gas supply pressure must be main-
tained to prevent unreliable ignition. The maximum must not be
exceeded to prevent unit overfiring.