Bryant Gas Air 393U - Manual (Page 5)

LOCATING THE UNIT
1. This gas furnace is approved for use on combus­
tible floors except when installed as a counter-flow
furnace. When installed as a counter-flow furnace
on a combustible floor it must be installed on an
approved base.
2. The furnace is A.G.A. approved for the following
clearances from combustible construction in a clos­
et or alcove installation.
Sides....................... 0" (!")*
Back........................0" (1")*
t Top of plenum. . . 3" (0")*
Vent connector . . 6" (6")*
Front....................... 6" (6")*
* Figures shown in parentheses are approved clear­
ances when the furnace is installed as a counter­
flow furnace.
t Refer to ASA Z21.30-1954 for clearances in open
area installations.
3. Locate the furnace as close to the chimney as
possible. The furnace should also be located as
centrally as possible to the distribution system.
4. Provide ample space for servicing and cleaning.
Consult your local approval agency for any special
clearance requirements.
5. The furnace should be level. Use shims as
required, if the floor or foundation is not completely
level.
6. Advise owner to leave all air passageways to
the furnace free of obstruction in order that there
will be no interference with combustion and venti­
lating air.
7. The furnace is designed for use with summer air
conditioning. Therefore consideration should be
given to leaving ample space for a later installation
of air conditioning equipment, if the air conditioning
equipment is not being installed as part of the orig­
inal furnace installation.
Bryant manufactures a coil box for upflow furnaces.
If air conditioning will be added at a later date, the
coil box, if installed on the original installation,
will save time and money later. A coil box is not
needed for counter-flow furnaces.
This gas furnace is not approved for use with air
conditioning units mounted upstream from the fur­
nace heat exchanger. The cooling coil should either
be downstream of the furnace heat exchanger or the
flow of cooling air should be by-passed around the
heat exchanger. If this parallel arrangement is used,
the dampers or other means used to control the flow
of air must be adequate to prevent chilled air from
entering the furnace. If these dampers are manually
operated, they must be equipped with means to pre­
vent operation of either unit unless the damper is
in the full heat or full cool position.
8. In general, when the furnace is installed in a
large open space, there will be enough air for com­
bustion and ventilation. However, when the unit is
installed in buildings of unusually air-tight con­
struction, or when the furnace is located in very
restricted spaces such as closets or utility rooms,
special provisions must be made for combustion,
ventilating, and draft hood dilution air.
When the unit is installed in a confined space, pro­
vide the confined space with two permanent open­
ings, one near the top of the enclosure and one near
the bottom. These openings must freely communicate
with interior areas that have adequate infiltration
air from the outside. Each opening must have a free
area of not less than one square inch for each
1000 Btu/hr of rated input of oil appliances located
within the enclosure.
If it is not practicable to connect the two openings
to interior space, or if the interior space has in­
sufficient infiltration air, then it is necessary to
connect the openings to the outside. If air openings
are directly to outdoors, the minimum free area
should be one square inch per 3000 Btu/hr of input
rating or in accordance with Z21.30-1964 or latest
edition, “American Standards for Installation of Gas
Appliances and Gas Piping.”
It is strongly recommended that the installer consult
the “American Standards Installation of Gas Ap­
pliances and Gas Piping,” ASA Z21.30-1964.
9. In restricted spaces it is very important that the
return air ducts be sealed firmly into the furnace so
that the return air will be kept separate from the
combustion and ventilating air.
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393U