G6RA, G6RK Service Manual 7
If a cooling system is installed in parallel with the furnace, a
damper must be installed to prevent chilled air from entering
the furnace and condensing on the heat exchanger. If a
manually operated damper is installed, it must be designed
so that operation of the furnace is prevented when the damper
is in the cooling position and operation of the cooling system
is prevented when the damper is in the heating position.
Return Air
In applications where the supply ducts carry heated air to
areas outside the space in which the furnace is installed, the
return air must be delivered to the furnace by duct(s) sealed
to the furnace casing, running full size and without interruption
between the outside space and the one in which the furnace
is installed.
WARNING
!
The solid base of the furnace must be in place
when the furnace is installed with side return air
ducts. Removal of all or part of the base could
cause products of combustion to be circulated
into the living space and create potentially
hazardous conditions, including carbon
monoxide poisoning that could result in personal
injury or death.
Products of combustion must not be allowed to
enter the return air ductwork or the circulating
air supply. Failure to prevent products of
combustion from being circulated into the living
space can result in personal injury or death.
All return ductwork must be adequately sealed,
all joints must be taped, and the ductwork must
be secured to the furnace with sheet metal
screws. When return air is provided through the
bottom of the furnace, the joint between the
furnace and the return air plenum must be sealed.
The floor or platform on which the furnace is
mounted must provide sound physical support
of the furnace with no gaps, cracks, or sagging
between the furnace and the floor or platform.
Return air and circulating air ductwork must not
be connected to any other heat producing device
such as fireplace insert, stove, etc.
WARNING
!
A clearance of at least 36 inches from the front of the furnace
is recommended to allow for servicing and maintenance.
Where accessibility clearances are greater than the
minimum clearances, accessibility clearances must take
precedence.
CIRCULATING AIR SUPPLY
General
Plenums and air ducts must be installed in accordance with
the Standard for the Installation of Air Conditioning and
Ventilating Systems (NFPA No. 90A) or the Standard for the
Installation of Warm Air Heating and Air Conditioning Systems
(NFPA No. 90B).
If outside air is utilized as return air to the furnace for
ventilation or to improve indoor air quality, the system must
be designed so that the return air to the furnace is not less
than 50°F (10°C) during heating operation. If a combination of
indoor and outdoor air is used, the ducts and damper system
must be designed so that the return air supply to the furnace
is equal to the return air supply under normal, indoor return air
applications.
When a cooling system is installed which uses the furnace
blower to provide airflow over the indoor coil, the coil must be
installed downstream (on the outlet side) or in parallel with the
furnace.
The return air ductwork may be connected to any or all of the
following: left side return, right side return, or bottom return.
Table 3 shows the airflow data for each furnace model.
Where maximum airflow is 1800 CFM or more, two
openings must be used.
To Next Page
Loading...
Need help?
General