# 47860A005
Page 20
The furnace must be grounded and wired in accordance
with local codes or, in the absence of local codes, with the
National Electrical Code ANSI/NFPA No. 70 (latest edition)
and/or CSA C22.1 Electrical Code (latest edition) if an
external electrical source is utilized.
In all instances, other than wiring for thermostat, the wiring
to be done and any replacement of wire shall conform with
the temperature limitation for Type T wire –63°F (35°C) rise.
Connect a sufficiently sized wire with ground to the furnace’s
line voltage connections and ground lug. Refer to the
furnace rating plate for electrical characteristics to be used
in sizing field supply wiring and over-current protection.
The line voltage supply should be routed through a readily
accessible disconnect located within sight of the furnace.
A junction box on the furnace side panel is provided for
line voltage connections. Refer to the furnace wiring
diagram for specific connection information.
Proper polarity of the supply connections (“HOT”
and “NEUTRAL”) must be observed to ensure that
safety controls provide the protection intended.
A connection to the ground lug and actual earth ground
(typically a ground stake or buried steel pipe) must be
maintained for proper operation.
Thermostat
Install a room thermostat according to the instructions
furnished with it. Select a location on an inside wall that is
not subject to drafts, direct sunshine, or other heat
sources. The initial heat anticipator setting should be
equal to the total current draw of the control circuit.
Low voltage thermostat connections are to be made to the
blower control board as indicated on the wiring diagram.
Continuous Low Speed Blower
If continuous blower operation on low speed is desired,
connect the lowest speed motor tap to the “CONT”
terminal on the blower control board (refer to the furnace
wiring diagram.) The blower will operate on low speed
whenever main power is connected to the furnace, except
when it operates on heating or cooling speed during
thermostat call for heat or cooling.
This constant air
terminal is intended for low speed only.
If a motor is
wired for a higher speed, the increased amp draw could
cause the board control to fail and void the warranty.
Humidifier
Terminals are provided on the blower control board for
connection to a 120-volt humidifier. The “HUM” terminal is
energized whenever the thermostat calls for heat. Refer to
furnace wiring diagram for specific connection information.
Electronic Air Cleaner
Terminals are provided on the blower control board for
connection of a 120-volt electronic air cleaner. The “EAC”
terminal is energized whenever the thermostat is calling for
heat, cooling, or continuous blower. Refer to the furnace
wiring diagram for specific connection information.
Twinning
The blower control board is designed to permit “twinning” of
furnaces (two furnaces connected to common supply and
return air system, and controlled by one thermostat). An
accessory kit must be ordered from manufacturer. Specific
wiring and operating instructions are included with the kit.
Each furnace must have its own dedicated vent system.
Filters
Filters are not supplied with CG90TB series furnaces but
their use if required. G1D91BT and G1D93BT furnaces come
with a filter rack and cleanable 16" x 25" x 1/2" filter. (Models
designed for more than 1600 CFM nominal air delivery
include two of each.) The filter rack is to be installed between
the return air duct and the side of the furnace.
If a filter other than one supplied by the furnace
manufacturer is used, it must be sized according to
information provided in Table 3.
Refer to Figure 31 and the following instructions to install
the filter rack:
1. Using the corner embossments as a guide, mark and
cut a full-size opening in the side panel(s).
2. Using the filter rack as a template, mark and drill four
7/64" diameter screw holes in the side panel(s).
3. With the filter access opening toward the front of the
furnace, use sheet metal screws to fasten the rack(s)
to the side panel(s).
The filter slides in the rack from the front of the unit. Install
the filter(s) with the mesh side towards furnace.
For units that do not include a side return filter rack, kit
AFILT524 can be used. Single side filter frame kit
AFILTHA7 is available for single side return air connection
in installations requiring more than 1600 CFM nominal air
delivery. Bottom return filter kit AFILT529 is also available
from the manufacturer.
