Ducting - Rheem GF902U Series Installation Instructions Manual

DUCTING

Proper air flow is required for the
correct operation of this furnace.
Too little air flow can cause erratic
operation and can damage the heat
exchanger. The duct system must
carry the correct amount of air for
heating and cooling if summer air
conditioning is used.
Size the ducts according to
acceptable industry standards and
methods. The total static pressure
drop of the air distribution system
should not exceed 0.5" w.c.
WARNING
NEVER ALLOW THE PRODUCTS
OF COMBUSTION FROM THE
FLUE TO ENTER THE RETURN AIR
DUCTWORK OR THE CIRCULATED
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. WHEN
AN UPFLOW FURNACE IS
MOUNTED ON A PLATFORM WITH
RETURN THROUGH THE BOTTOM,
IT MUST BE SEALED AIRTIGHT
BETWEEN THE FURNACE AND
THE RETURN AIR PLENUM. THE
FLOOR OR PLATFORM MUST
PROVIDE SOUND PHYSICAL
SUPPORT OF THE FURNACE
WITHOUT SAGGING, CRACKS, OR
GAPS, AROUND THE BASE,
PROVIDING A SEAL BETWEEN
THE SUPPORT AND THE BASE.
FAILURE TO PREVENT
PRODUCTS OF COMBUSTION
FROM BEING CIRCULATED INTO
THE LIVING SPACE CAN CREATE
POTENTIALLY HAZARDOUS
CONDITIONS, INCLUDING
CARBON MONOXIDE POISONING
THAT COULD RESULT IN
PERSONAL INJURY OR DEATH.
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
OR PROPERTY DAMAGE.
IMPORTANT: Some high efficiency
filters have a greater than normal
resistance to air flow. This can
adversely affect furnace operation.
BE SURE TO CHECK AIR FLOW.
IMPORTANT: When using outside air,
design and adjust the system to maintain
a return air temperature ABOVE 55° F
during the heating season.
NOTE: Return air grilles and warm air
registers must not be obstructed or
closed.
UPFLOW UNITS
1. Position the unit to minimize long
runs of duct or runs of duct with
many turns and elbows.
2. Open the return air compartment.
WARNING
UPFLOW FURNACE: A SOLID METAL
BASE PLATE MUST REMAIN IN THE
FURNACE BOTTOM WHEN USING
SIDE AIR RETURN. FAILURE TO
INSTALL A BASE PLATE COULD
CAUSE THE PRODUCTS OF
COMBUSTION TO CIRCULATE INTO
THE LIVING SPACE AND CREATE
POTENTIAL LY HAZARDOUS
CONDITIONS, INCLUDING CARBON
MONOXIDE POISONING OR DEATH.
FOR BOTTOM RETURN, REMOVE
SOLID METAL BASE PLATE.
a. Cut an opening in the side. The
opening should be cut the full
width and height of the knockouts
on the unit. See Figure 8.
FIGURE 8
UPFLOW CUTOUT AND DRILL INFORMATION
JACKET
NOTE: Where the maximum air flow
is 1800 CFM or more, both sides or
the bottom must be used for return
air.
3. Connect the return duct or return
air cabinet to the unit. Make the
connection air tight to prevent
entraining combustion gases
from an adjacent fuel-burning
appliance.
4. Be sure to have adequate
space for the unit filter.
NOTE: DO NOT take return air
from bathrooms, kitchens,
furnace rooms, garages, utility or
laundry rooms, or cold areas.
NOTE: DO NOT use a rear air
return.
5. If summer air conditioning is
desired, position the indoor coil
on the supply-air side of the unit.
Insure that no air can bypass this
coil.
6. Connect the supply air plenum to
the furnace plenum opening.
IMPORTANT: If a flexible duct
connector must be used, it
MUST be rated for a minimum
temperature of 250°F.
continuous.
DRILL (2)
3/16" DIA.
HOLES
8.000
4.875
1.531
13 13