SYSTEM OPERATION
25
used, a connecting duct must be installed between the unit
and the utility room wall so the blower will not interfere with
combustion air or draft. The room, closet, or alcove must not
be used as a return air chamber.
When the furnace is used in connection with a cooling unit,
the furnace should be installed in parallel with or on the
upstream side of the cooling unit to avoid condensation in
the heating element. With a parallel ๎ow arrangement, the
dampers or other means used to control the ๎ow of air must
be adequate to prevent chilled air from entering the furnace
and, if manually operated, must be equipped with means to
prevent operation of either unit unless the damper is in the
full heat or cool position.
When the furnace is heating, the temperature of the return
air entering the furnace must be between ๎๎๎๎ฉ and ๎๎๎๎๎ฉ.
๎ธ๎ณ๎ต๎ฌ๎ช๎ซ๎ท๎๎ฉ๎ฌ๎ฏ๎ท๎จ๎ต๎๎ฌ๎ฑ๎ถ๎ท๎ค๎ฏ๎ฏ๎ค๎ท๎ฌ๎ฒ๎ฑ๎ถ
Depending on the installation and/or customer preference,
di๓ฐจering ๎ฟlter arrangements can be applied. Filters can be
installed in the central return register and a side panel external
๎ฟlter rack kit (up๎ow ๎ฟlter kit # EFR02). As an alternative
a media air ๎ฟlter or electronic air cleaner can be used as
the requested ๎ฟlter. Refer to the following minimum ๎ฟlter
requirement charts for determination of the minimum ๎ฟlter area
to ensure proper unit performance. ๎ท๎๎๎๎๎๎๎๎๎๎๎๎ ๎ฟ๎๎๎๎๎๎
show possible ๎ฟlter locations. ๎ฑ๎ฒ๎ท๎จ๎ A ductwork access
door must be used in counter๎ow applications to allow ๎ฟlter
removal. If the ๎ฟlter rack is used, the side of the plenum must
be at least as tall as dimension โAโ shown in the following
illustration. For dimension of โAโ refer to the following chart.
Refer to Minimum Filter Area tables to determine ๎ฟlter area
requirement. ๎ฑ๎ฒ๎ท๎จ๎ Filters can also be installed elsewhere
in the duct system such as a central return.
๎ซ๎๎๎๎๎๎๎๎๎๎๎ฌ๎๎๎๎๎๎๎๎๎๎๎๎
Filter(s) must be installed external to the furnace casing for
horizontal installations. For most installations it is preferable
to use a central return with ๎ฟlters installed in the duct behind
the return air grill. In this way ๎ฟlter replacement is relatively
simple by merely removing the grille, rather than going into
the attic or crawl space.
๎ค๎ง๎ง๎ฌ๎ท๎ฌ๎ฒ๎ฑ๎ค๎ฏ๎๎ฉ๎ฌ๎ฏ๎ท๎จ๎ต๎ฌ๎ฑ๎ช๎๎ค๎ฆ๎ฆ๎จ๎ถ๎ถ๎ฒ๎ต๎ฌ๎จ๎ถ
๎จ๎๎๎๎๎๎๎๎๎ฉ๎๎๎๎๎๎๎ต๎๎๎๎๎ฎ๎๎๎๎๎จ๎ฉ๎ต๎๎๎
The external ๎ฟlter rack kit is intended to provide a location
external to the furnace casing, for installation of a permanent
๎ฟlter on up๎ow model furnaces. The rack is designed to mount
over the indoor blower compartment area of either side panel,
and provide ๎ฟlter retention as well as a location for attaching
return air ductwork.
๎จ๎๎๎๎๎๎๎๎๎๎๎ค๎๎๎๎ฆ๎๎๎๎๎๎๎๎๎ค๎ถ๎ค๎ถ๎๎๎๎๎๎ช๎ถ๎ค๎ถ๎๎๎๎๎๎ฐ๎๎๎๎๎๎ค๎๎๎
๎ฆ๎๎๎๎๎๎๎๎๎ค๎ฐ๎ธ๎๎๎๎๎๎ช๎ฐ๎ธ๎
The electronic air cleaner and media air cleaner are multi-
positional high e๓ฐฉciency air ๎ฟltration devices that can be
installed in any position, except with the access door facing
down. The best location for the air cleaner is in the return
air duct next to the blower compartment. Before installing
the air cleaner, consider the application. The electronic air
cleaner must be readily accessible for periodic inspection and
cleaning of the pre-๎ฟlters and electronic cells while the media
air cleaner must be readily accessible for periodic inspection
and replacement of the Media Air Cleaner (AMU and GMU)
๎ฟlter cartridge (3 per carton) M0-1056, M1-1056, M2-1056,
M8-1056, to maintain maximum e๓ฐฉciency and trouble-free
operation. Carbon Filters 1156-3 and 1856-3 (set of 3) are also
available. See Product Catalog for exact ๎ฟlter for your model.
๎ฑ๎ฒ๎ต๎ฐ๎ค๎ฏ๎๎ถ๎จ๎ด๎ธ๎จ๎ฑ๎ฆ๎จ๎๎ฒ๎ฉ๎๎ฒ๎ณ๎จ๎ต๎ค๎ท๎ฌ๎ฒ๎ฑ
๎ณ๏๏๏๏๎๎ธ๏
1. 115 VAC power applied to furnace.
2. Integrated ignition control module performs internal
checks.
3. Integrated ignition control module LED will light.
4. Integrated ignition control monitors safety circuits contin-
uously.
5. Furnace awaits call from thermostat.
๎ฑ๏๏๏๏๏๎๎ซ๏๏๏๏๏๏๎๎ถ๏๏๏๏๏๏๏๎
1. R and W thermostat contacts close, initiating a call for
heat.
2. Integrated control module performs safety circuit checks.
3. The induced draft blower is energized causing pressure
switch contacts to close. Induced draft blower remains
energized for pre-purge period.
4. Ignitor warm up begins after pre-purge is completed.
The ignition control has a WARM UP PERIOD OF 17
SECONDS.
5. Gas valve opens at end of ignitor warm up period, deliv-
ering gas to burners to establish ๎ame.
6. The control checks for a signal from the ๎ame sensor
within seven (4) seconds after the gas valve is energized.
Gas will only continue to ๎ow if a ๎ame signal is present.
7. Circulator blower is energized on heat speed following a
๎ฟxed thirty (30) second blower on delay.
8. Furnace runs, integrated control module monitors safety
circuits continuously.
9. R and W thermostat contacts open, allowing the gas valve
to cycle o๓ฐจ.
10. Induced draft blower is de-energized following a ๎ฟfteen
(15) -second post purge.
11. Circulator blower is de-energized following heat o๓ฐจ delay
period.
12. Furnace awaits next call from thermostat.