Installation Guide

18
Damper must be in open position when appliance main burner(s)
is operating.
When the furnace is installed without a cooling coil, it is
recommended that a removable access panel be provided in the
outlet air duct. This opening shall be accessible when the furnace
is installed and shall be of such a size that the heat exchanger can
be viewed for visual light inspection or such that a sampling probe
can be inserted into the airstream. The access panel must be made
to prevent air leaks when the furnace is in operation.
NOTE: In a horizontal installation the air conditioning coil must
be adequately supported by proper brackets and supports.
Inadequate coil support can result in furnace cabinet distortion
and air leakage.
When the furnace is heating, the temperature of the return air
entering the furnace must be between 55°F and 100°F.
When a furnace is installed so that supply ducts carry air circulated
by the furnace to areas outside the space containing the furnace,
the return air shall also be handled by a duct sealed to the furnace
casing and terminating outside the space containing the furnace.
FILTERS - READ THIS SECTION BEFORE INSTALLING THE RETURN AIR
DUCTWORK
Filters must be used with this furnace. Filters do not ship with this
furnace, but must be provided by the installer. Filters must comply
with UL900 or CAN/ULCS111 standards. Damage or repairs due to
failure to install filters in the furnace are not covered under the
warranty.
UPRIGHT I NSTALLATIONS
Depending on the installation and/or customer preference,
differing filter arrangements can be applied. Filters can be
installed in the central return register or a side panel external
filter rack kit (upflows), or the ductwork above a downflow furnace.
As an alternative, a media air filter or electronic air cleaner can
be used as the primary filter.
One of the most common causes of a problem in a forced air
heating system is a blocked or dirty filter. Air filters must be
inspected monthly for dirt accumulation and replaced if necessary.
Failure to maintain clean filters can cause premature heat
exchanger failure.
A new home may require more frequent replacement until all
construction dust and dirt is removed. Circulating air filters are to
be installed in the return air duct external to the furnace cabinet.
Upflow / Horizontal
Models
Minimum Recommended Filter Size^
*0403A* 1 - 16 X 25 Side or 1 - 14 X 24 Bottom Return
*0603A* 1 - 16 X 25 Side or 1 - 14 X 24 Bottom Return
*0604B* 1 - 16 X 25 Side or Bottom Return
*0803B* 1 - 16 X 25 Side or Bottom Return
*0804B* 1 - 16 X 25 Side or Bottom Return
*0805C* 1 - 16 X 25 Side or Bottom Return¹
*0805D* 2 - 16 X 25 Side or 1 - 20 X 25 Bottom Return
*1005C* 2 - 16 X 25 Side or 1 - 20 X 25 Bottom Return
*1205D* 2 - 16 X 25 Side or 1 - 24 X 24 Bottom Return
Downflow Models Minimum Recommended Filter Size^
*0403A* 2 - 10 X 20 or 1 - 14 X 25 Top Return
*0603A* 2 - 10 X 20 or 1 - 14 X 25 Top Return
*0804B* 2 - 14 X 20 or 1 - 16 X 25 Top Return
*1005C* 2 - 14 X 20 or 1 - 20 X 25 Top Return
^ Larger filters may be used, filters may also be centrally located
¹ = us e 2 - 16 X 25 filters and two s ide returns or 20 X 25 fi lter on bottom
return if furnace is connected to a cooling unit over 4 tons nominal capacity
HORIZONTAL I NSTALLATIONS
Filters must be installed in either the central return register or in
the return air duct work.
S EQUENCE OF O PERATION (I NTEGRATED I GNITION C ONTROL )
Refer to Timing Charts for sequencing.
POWER UP
• 115 VAC power applied to furnace.
• Integrated ignition control performs internal checks.
• Integrated ignition LED will light.
• Integrated ignition control monitors safety circuits
continuously.
• Furnace awaits call from thermostat.
HEATING M ODE
The normal operational sequence in heating mode is as follows:
• R and W thermostat contacts close, initiating a call for
heat.
• Integrated control module performs safety circuit checks.
• Induced draft blower is energized for 15 second pre-purge
period causing pressure switch contacts to close.
• Igniter warm up begins after 15 second prepurge expires.
• Gas valves open at end of igniter warm up period, delivering
gas to burners and establishing flame.
• Integrated control module monitors flame presence. Gas
valve will remain open only if flame is detected.
• Circulator blower is energized on high heat speed following
a fixed thirty second blower on delay. Electronic air cleaner
terminals are energized with circulator blower.