I Combination Units Installation Instructions
5. Electrical Wiring
Electrical shock hazard.
Disconnect power at fuse box or service panel before
making any electrical connections.
Unit MUST be grounded to electrical service panel.
Failure to follow this warning can result in property
damage, personal injury, and/or death.
The location of the thermostat has an important effect on the op-
eration of the unit. FOLLOW THE INSTRUCTIONS INCLUDED
WITH THE THERMOSTAT FOR CORRECT LOCATION,
MOUNTING, AND WIRING.
Heat Anticipator
Set the thermostat heat anticipator to. 58 in accordance with ther-
mostat instructions.
Line Voltage Wiring
Connections for line voltage are made in the unit control box. For
access, remove the burner access panel and the control box cov-
er.
NOTE: All electrical work MUST conform with the requirements of
local codes and ordinances and the National Electrical Code
ANSI/NFPA-No. 70-1990 or current edition. Provide line voltage
power supply from a separate protected circuit with a disconnect
switch (when required) located within sight of the unit. Supplyvolt-
age, amperage, wire, fuse and disconnect switch sizes MUST
conform with specifications in the Technical Support Manual and
with unit rating plate.
All exposed wiring or connections MUST be made with weather-
proof cable or wire unless installed in conduit. Wiring MUST be
protected from possible mechanical damage.
Connections for line voltage are made in the unit control box. Low
voltage connections are made outside the control box. For ac-
cess, remove the burner access panel and the control box cover.
See FIGURE 2.
Low Voltage Wiring
Low voltage wiring connections for the thermostat are made atthe
24Vterminal board outside the control box. Refer to the wiring dia-
gram for the applicable model and the instructions included with
the thermostat.
Do NOT complete line voltage connections until unit is perma-
nently grounded. All line voltage connections and the ground con-
nection MUST be made with copper wire.
Ground Connections
A ground lug is installed in the control box for the ground connec-
tion. Use a copper conductor of the appropriate size from the unit
to a grounded connection in the electrical service panel.
Line Connections
Complete the line service connections to the contactor 'L' termi-
nals inside the control box. Refer to applicable wiring diagram in
Technical Support Manual. Check all screw terminals to ensure
they are tight.
Field Installed Equipment
Wiring to be done in the field between the unit and devices not at-
tached to the unit, or between separate devices which are field
installed and located, shall conform with the temperature limita-
tions for type T wire and shall be installed with the manufacturer's
instructions applicable to such devices.
Thermostat
NOTE: Do NOT attempt to use a thermostat designed for
electric heat or heat pump use. Such thermostats will NOT
control the unit properly,
Final Electrical Check
Make a final wiring check to be sure system is correctly wired. In-
spect field installed wiring and the routing to ensure that rubbing or
chafing due to vibration will not occur.
6. Ductwork
Maximum recommended velocity in trunk ducts is 1000 feet per
minute. Velocity in branches should not exceed 800 feet per min-
ute.
NOTE: Ductwork sizing affects temperature rise and cooling tem-
perature differential. Be sure to properly size ductwork to the ca-
pacity and airflow characteristics of your unit. Failure to do so can
affect limit controls, compressors, motors, and other components
and will lead to premature failure of components. This will also
adversely affect day to day unit performance. Refer to rating plate
and Temperature Rise Check section in this manual.
Ductwork Insulation
Ductwork installed outdoors should have a minimum of 2" Fiberg-
las insulation and a weatherproof vapor barrier. It should be pro-
tected against damage. Caulking and flashings, or other means
adequate to provide a permanent weather seal, should be used.
Ductwork installed in attics or other areas exposed to outside tem-
peratures should be installed with a minimum of 2" Fiberglas in-
sulation and have an indoor type vapor barrier.
Ductwork Connections
The use of flexible, non-combustible connectors between main
trunk ducts and supply and return air plenums is recommended to
minimize vibration transmission.
NOTE: Connect supply and return air plenums to unit in a manner
that will allow the top of the unit to be removed without removing
plenums. Plenums MUST be individually sealed to unit casing
with ducts terminating inside structure.
50901 110202
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