Ducting - Rheem Gra 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.
NOTE: Return air grilles and warm air
registers must not be obstructed
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 50° F during the heating
season.
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 BE
INSTALLED IN THE FURNACE
BOTTOM WHEN USING SIDE
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.
a. Cut an opening in the side.
The opening should
be cut the full width of the
knockouts on the unit. See
Figure 9.
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.
FIGURE 9
CUTOUT AND DRILL INFORMATION
JACKET
5. If summer air conditioning is
desired, position the indoor coil
on the top 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.
DOWNFLOW UNITS
1. Position the unit to minimize long
runs of duct or runs of duct with
many turns and elbows.
2. If summer air conditioning is
desired, position the indoor coil
on the bottom of the unit. Insure
that no air can bypass this coil.
3. If installing on a combustible floor
and not using an air
conditioning plenum, install the
special non-combustible floor
base. See Figure 10.
WARNING
!
THE DOWNFLOW FURNACE
DESIGN IS CERTIFIED FOR
INSTALLATION ON A NON-
COMBUSTIBLE FLOOR. USE THE
SPECIAL BASE SPECIFIED ON
THE FURNACE CLEARANCE
LABEL. FAILURE TO INSTALL THE
SPECIAL BASE MAY RESULT IN
FIRE, PROPERTY DAMAGE,
PERSONAL INJURY OR DEATH.
THIS SPECIAL BASE IS SHIPPED
FROM THE FACTORY AS AN
ACCESSORY.
DRILL (2)
3/16" DIA.
HOLES
8.000
4.875
1.531
13 13