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CIRCULATING AIR SUPPLY
Plenum chambers 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.
The circulating air supply may be
taken: (1) exclusively from return air
ducts from several rooms, or (2)
combined with outside air. When
outside air is utilized, the system
should be designed and adjusted such
that the temperature of the combined
return air to the furnace will not be
below 50°F during the heating season.
When using a combination of outside
air and return air, be sure the ducts are
so designed and a diverting damper so
installed that the volume of circulating
air entering the furnace cannot be
reduced or restricted below that which
would normally enter through the
circulating air intake of the furnace.
When the furnace is installed so that
the supply ducts carry air circulated by
the furnace to areas outside the space
containing the furnace, the return air
shall be handled by a duct or ducts
sealed to the furnace casing and
terminated outside the space
containing the furnace.
WARNING
!
IF THERE IS NO COMPLETE
RETURN AIR DUCT SYSTEM, THE
RETURN AIR CONNECTION MUST
RUN FULL SIZE TO A LOCATION
OUTSIDE THE UTILITY ROOM OR
SPACE HOUSING THE FURNACE
TO PREVENT A NEGATIVE
PRESSURE ON THE VENTING
SYSTEMS. A NEGATIVE PRESSURE
CAN DRAW PRODUCTS OF
COMBUSTION INTO CIRCULATING
AIR.
NEVER ALLOW THE PRODUCTS OF
COMBUSTION OR THE FLUE
PRODUCTS TO ENTER THE RETURN
AIR DUCTWORK OR THE
CIRCULATING AIR SUPPLY. ALL
RETURN DUCTWORK MUST BE
ADEQUATELY SEALED AND
SECURED TO THE FURNACE WITH
SHEET METAL SCREWS, AND
JOINTS TAPED. ALL OTHER DUCT
JOINTS MUST BE SECURED WITH
APPROVED CONNECTIONS AND
SEALED AIRTIGHT.
FAILURE TO PREVENT PRODUCTS
OF COMBUSTION FROM BEING
CIRCULATED INTO THE LIVING
SPACE CAN CREATE SOOT
DAMAGE, SMOKE, ODORS OR
CARBON MONOXIDE POISONING.
IMPORTANT: One of the most
common causes of trouble in forced air
heating systems is insufficient return
air to the furnace. The return air
system should be approximately equal
to or greater than the area of the warm
air discharge. CONSULT LOCAL
CODES FOR SPECIAL
REQUIREMENTS.
WARNING
!
DO NOT, UNDER ANY
CIRCUMSTANCES, CONNECT
RETURN OR SUPPLY DUCTWORK
TO OR FROM ANY OTHER HEAT
PRODUCING DEVICE SUCH AS A
FIREPLACE INSERT, STOVE, ETC.
DOING SO MAY RESULT IN FIRE,
CARBON MONOXIDE POISONING,
EXPLOSION, PERSONAL INJURY,
PROPERTY DAMAGE OR DEATH.
Install the cold air return to terminate
through the floor under the furnace. A
direct connection should be made to
the bottom of the furnace. For
installations where return air ducts
cannot be run under the floor, return air
may be taken from the sides by cutting
the furnace casing and installing the
appropriate accessory.
NOTE: Where the maximum air flow is
1800 CFM or more, both sides or the
bottom must be used for return air.
When a cooling coil is used in
conjunction with the furnace, it must be
installed downstream of the outlet end
of the furnace (supply-air side) or in
parallel with the furnace to avoid
condensation in the heat exchanger.
If the furnace is installed in parallel with
a cooling unit, the damper or other
means used to control the flow 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 the
other unit unless the damper is in the
full heat or cool position.
IMPORTANT: Air openings in the
casing front, return air grilles and warm
air registers must not be obstructed.
WARNING
!
BLOWER AND BURNERS MUST
NEVER BE OPERATED WITHOUT
BLOWER DOOR IN PLACE. THIS IS
TO PREVENT DRAWING FUMES
(WHICH COULD CONTAIN
ANNOYING AND HAZARDOUS
GASES) INTO THE HOME THAT
COULD RESULT IN PERSONAL
INJURY OR DEATH.
FLUE AND CHIMNEY
EXHAUST
The vent connector should be as short
as possible and installed so that it has
a continuous rise from the furnace to
the chimney or flue.
The number of elbows should be
minimized and the flue pipe should be
joined with sheet metal screw and
properly supported with suitable pipe
hangers.
A barometric draft regulator is required
in each furnace vent connector and
must be installed before the vent
connector enters the chimney or flue.
NOTE: The size of the draft regulator
diameter must be no smaller than the
vent connector diameter.
The vent connector should be the
same size as the furnace flue pipe
connection. The sizes are:
TABLE 4
BTU OUTPUT
FLUE SIZE
056
067
084
095
112
130
150
CHIMNEY SIZE
RECOMMENDATIONS
The following table shows
recommended size and height for
chimneys based on total BTU input of
all the oil appliances being vented:
TABLE 5
GROSS BTU RECTANGULAR ROUND MINIMUM
INPUT
TILE
TILE
(INCHES)
(INCHES)
144,000
8
/
x 8
/
8
1
1
2
2
235,000
8
1
/
x 13
10
2
372,000
13 x 13
12
516,000
13 x 18
14
612,000
—
15
768,000
18 x 18
—
960,000
20 x 20
18
VENTING
Unit must be vented through a chimney
or flue. Check chimney for soot, leaks,
obstruction and proper height to
prevent down draft. Clean chimney and
base if necessary.
The height of the chimney or flue shall
be at least 3 feet above the highest
point where it passes through the roof
of a building and at least 2 feet higher
than any portion of a building within 10
feet of such chimney.
5"
5"
5"
5"
5"
7"
7"
HEIGHT
(FEET)
20
30
35
40
45
50
55
9
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