GMS8 Installation Manual
18
EAC-H
Line
Transformer
Line
Transformer
EAC
Air Cleaner
Control Module
Hot 120 VAC
Neutral 120 VAC
Optional
Accessories
GME8, AMEH8, GDH8, ADSH8 & (A/G)MH8 MODELS ONLY
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 junction
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.
NOTE: Do not remove the gas valve inlet plug before the gas line
is installed. Replace if water or debris has been introduced.
Natural Gas Minimum: 4.5" w.c. Maximum: 10.0" w.c.
Propane Gas Minimum: 11.0" w.c. Maximum: 13.0" w.c.
INLET GAS SUPPLY PRESSURE
NOTE: Adjusting the minimum supply pressure below the limits in
the above table could lead to unreliable ignition. Gas input to the
burners must not exceed the rated input shown on the rating plate.
Overfiring of the furnace can result in premature heat exchanger
failure. Gas pressures in excess of 13 inches water column can
also cause permanent damage to the gas valve.
At all altitudes, the manifold pressure must be within 0.3 inches
w.c. of that listed in the Specification Sheet applicable to your
model for the fuel used. At all altitudes and with either fuel, the air
temperature rise must be within the range listed on the furnace
nameplate. Should this appliance be converted to LP, refer to the
instructions included in the factory authorized LP conversion kit.
HIGH ALTITUDE DERATE
IM PORTANT NOTE: The furnace, as shipped, requires no change to
run between 0 - 5500 feet. Do not attempt to increase the firing rate
by changing orifices or increasing the manifold pressure below
5500 feet. This can cause poor combustion and equipment failure.
High altitude installations above 5500 feet may require both a
pressure switch and an orifice change. These changes are neces-
sary to compensate for the natural reduction in the density of both
the gas fuel and the combustion air at higher altitude.
For installations above 5500 feet, please refer to your distributor
for required kit(s).
Contact the distributor for a tabular listing of appropriate
manufacturer’s kits for propane gas and/ or high altitude installa-
tions. The indicated kits must be used to insure safe and proper
furnace operation. All conversions must be performed by a quali-
fied installer, or service agency.
PROPANE GAS CONVERSION
WARNING
P
OSSIBLE
PROPERTY
DAM AGE
,
PERSONAL
INJURY
OR
DEATH
M AY
OCCUR
IF
THE
CORRECT
CONVERSION
KITS
ARE
NOT
INSTALLED
. T
HE
APPROPRIATE
KITS
M UST
BE
APPLIED
TO
ENSURE
SAFE
AND
PROPER
FURNACE
OPERATION
. A
LL
CONVERSIONS
M UST
BE
PERFORM ED
BY
A
QUALIFIED
INSTALLER
OR
SERVICE
AGENCY
.
This unit is configured for natural gas. The appropriate
manufacturer’s propane gas conversion kit, must be applied for
propane gas installations. Refer to the “ Propane Gas and/ or High
Altitude Installations” section for details.
If converting to LP gas, it is recommended that an LPLP0* kit also
be installed. The use of this kit will prevent the furnace from firing
when the LP gas supply pressure is too low to support proper
combustion.