CONQUEST 90 - Supply and Return Air Ducting; Supply Air Ducting

SUPPLYAND
RETURNAIR DUCTING
SUPPL VAIR DUCTING
The supply air ducts must be sized
and designed to carry the required
air flow (in CFM) with minimal
restriction and pressure drop. Use
design and sizing methods that are
recognized by the HVAC industry
and apply to the type of duct material
used.
Install plenum chambers and air
ducts 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. 908.
If the supply ducts pass through
unconditioned spaces they must be
insulated according to industry
standards and meet all local codes. If
the supply ducts carry cooled air
during the summer months, they
must be protected with a vapor
barrier as well as insulation.
IMPORTANT: IF FLEXIBLE DUCT
CONNECTION MATERIAL IS USED
TO CONNECT THE SUPPLY
DUCTS TO THE FURNACE
OUTLET AIR PLENUM, THE
MATERIAL MUST MEET ALL NFPA
AND ANSI STANDARDS AND
HAVE
A MINIMUM CONTINUOUS
TEMPERATURE RATING OF 250°F.
NOTE: The supply plenum on the
furnace should have a removable
access panel. It should be accessible
after installation to visually check the
heat exchanger. It also enables a
service person to visually check the
air inlet side of an evaporator coil for
dirt, dust or other obstructions.
RETURN AIR DUCTING
AwARNING:
1. NEVER ALLOW THE
PRODUCTS OF COMBUSTION
FROM THE FLUE TO ENTER
THE RETURN AIR SYSTEM.
2. ALL RETURN AIR DUCTS
MUST BE ADEQUATELY
SEALED AND SECURED TO
THE FURNACE WITH SHEET
MET AL SCREWS AND TAPED
JOINTS. SECURE ALL OTHER
DUCT JOINTS WITH
APPROVED CONNECTIONS
AND SEAL AIRTIGHT.
3. WHEN MOUNTING AN
UPFLOW FURNACE ON A
PLATFORM WITH RETURN
THROUGH THE BOTTOM,
SEAL THE FURNACE TO THE
RETURN AIR PLENUM.
4. THE FLOOR OR PLATFORM
MUST SUPPORT THE
FURNACE WITHOUT SAG-
GING, CRACKS, OR GAPS
AROUND THE BASE, PROVID-
ING A SEAL BETWEEN THE
SUPPORT AND THE BASE.
5. DO NOT ALLOW PRODUCTS
OF COMBUSTION TO CIRCU-
LATE INTO THE LIVING
SPACE.
6. DO NOT CONNECT RETURN
OR SUPPLY AIR DUCTS TO
OR FROM ANY OTHER HEAT
PRODUCING APPLIANCE
SUCH AS A FIREPLACE
INSERT, STOVE, ETC.
FAILURE TO OBSERVE THESE SIX
(6) WARNING STATEMENTS MAY
RESULT IN FIRE, CARBON
MONOXIDE POISONING,
EXPLOSION, PERSONAL INJURY
OR PROPERTY DAMAGE.
Return air may come from:
(1) outside the building, (2) from
return air ducting from several inside
rooms, or (3) a combination of the
two. When using outside air, design
and adjust the system to maintain a
return air temperature
above 50°F
during the heating season. If return
air comes from both inside and
outside the building, design the
ducting system with a diverting
damper so that the volume of return
air entering the furnace equals that
which would normally enter through
the return air intake of the furnace.
Anyduct opening pulling return air
from the outside must not be any
higher nor closer than 10 feet to the
furnace exhaust vent.
If the supply ducts carry air to areas
outside the space containing the
furnace, the return ai~ duct or ducts
must be sealed to the furnace casing
and terminate outside the space
containing the furnace. If there is no
complete return air duct system, the
return air connection must be sealed
to the furnace casing and run full
size to a location outside the utility
room or space housing the furnace
to prevent a negative pressure on
any venting system.
DO NOT take
return air from a confined utility
room containing combustion
producing appliances.
Any evaporator cooling coil must be
installed downstream of the furnace
(at the outlet end of the furnace) or in
parallel with the furnace to avoid
condensation on the heat exchanger.
If the furnace is installed parallel with
a cooling unit, a damper, or other air
flow control must be installed to
prevent chilled air from entering the
furnace. If this device is manually
operated, it must have a means to
prevent operation of the other unit
unless the damper is in the full heat
or cool position.
IMPORTANT: ONE OF THE MOST
COMMON CAUSES OF FORCED
AIR HEATING PROBLEMS IS
INSUFFICIENT RETURN AIR TO
THE FURNACE. THE RETURN AIR
SYSTEM AREA SHOULD BE
APPROXIMATELY EQUAL TO OR
GREATER THAN THE AREA OF
THE WARM AIR DISCHARGE.
CONSULT LOCAL CODES FOR
SPECIAL REQUIREMENTS.
BLOWER SPEED SHOULD BE
ADJUSTED TO MAINTAIN THE AIR
TEMPERATURE RISE RANGE
SHOWN ON THE RATING PLATE.
52