Lennox MPGA 050 B3, Application Manual

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The furnace cabinet must have an uninterrupted or unbroken electrical ground to minimize personal injury if an
electrical fault should occur. The unit must also be electrically grounded in accordance with local codes, or in the
absence of local codes, with the latest edition of the (U.S.) National Electrical Code ANSI/NFPA No. 70 or CSA
Standard C22.1; Part 1 Canadian Electrical Code, if an external electrical source is utilized. DO NOT use gas piping
as an electrical ground.
INTRODUCTION
This furnace is design certified by CSA International as a Category I furnace using air from inside the structure for
combustion.
It is shipped as a packaged unit, complete with burners and controls, and requires a line voltage (115V) connection to
the junction box, a thermostat hook-up as per the wiring diagram and a gas line connection. This furnace can be installed
in either upflow, downflow or horizontal airflow positions. The design of this furnace is NOT CSA Certified for
installation in recreation vehicles, in manufactured (mobil) homes, outdoors or for temporary construction heating.
This furnace has been designed to interface with split system cooling equipment (approved by a nationally recognized
testing laboratory) so as to provide "year round air conditioning". The blower has been sized for both heating and cooling
and the furnace controls include a cooling fan relay.
The furnace installation must conform with local building codes or in the absence of local codes, with the latest edition
of the (U.S.) National Fuel Gas Code ANSI Z223.1 (NFPA-54) or Canadian Natural Gas and Propane Installation Codes
CSA B149.1.
For complete information on installation standards consult the (U.S.) National Fuel Gas Code, obtainable from the
National Fire Protection Association, Inc., Batterymarch Park, Quincy, MA 02269 or the American Gas Association, 1515
Wilson Boulevard Arlington, VA 22209 or the Canadian installation codes obtainable from Canadian Standards Association,
178 Rexdale Boulevard, Etobicoke, Ontario, Canada M9W 1R3.
This furnace is designed for minimum continuous return-air temperature of 60°F dB or intermittent operation down to
55°F dB such as when used with a night setback thermostat. Return-air must not exceed a maximum continuous
temperature of 85°F dB.
These instructions are written for individual residential installation only. For multi-unit installation or
commercial applications, please contact manufacturer for recommendations.
LOCATION / PLACEMENT
Site Selection
: This furnace may be located in an attic, closet, basement, crawl space, alcove or suspended from the
ceiling of a utility room or basement. Select a location that will meet all requirements for safety,
clearances, ventilation and combustion air, ductwork design, gas piping, electrical wiring and venting.
Clearances: The following minimum clearances, or greater, must be provided between the furnace and adjacent
construction.
TABLE 1
MINIMUM INSTALLATION CLEARANCES
"UPFLOW"
POSITION
"DOWNFLOW"
POSITION
"HORIZONTAL"
POSITION
Suitable for alcove or closet
installation† on combustible
flooring at minimum
clearance from adjacent
construction not less than
the following: Suitable for alcove or closet installation† on non-
combustible flooring at minimum clearance from
adjacent construction not less than the following:
* Installation on combustible flooring only when
installed on special base (see model & rating label
for proper special base). Suitable for attic, alcove or closet installation† on
combustible flooring at minimum clearance from
adjacent construction not less than the following:
* Line contact only permissible between lines
formed by intersection of the top and two sides of
the furnace jacket and building joist, studs, or
framing.
Top Sides Back Front Vent
2" 1" 1" 6" 6" with single wall vent
2" 1" 1" 3" 1" with B1 vent
† For closet installation see Air for Combustion and Ventilation.
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