Rheem GF951U Series - Ducting

13
DUCTING
P
roper air flow is required for the
c
orrect operation of this furnace.
T
oo little air flow can cause erratic
o
peration and can damage the heat
e
xchanger. The duct system must
c
arry the correct amount of air for
h
eating and cooling if summer air
c
onditioning 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.
&',Return air grilles and warm air
registers must not be obstructed
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!%('*,&,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.
!%('*,&,When using outside
air, design and adjust the system to
maintain a return air temperature
ABOVE 50° F during the heating
season.
-($'/-&!,+
1. Position the unit to minimize long
runs of duct or runs of duct with
many turns and elbows.
2. Open the return air compartment.
-($'/-*&A SOLID
METAL BASE PLATE MUST BE
INSTALLED IN THE FURNACE
BOTTOM WHEN USING SIDE
RETURN. FAILURE TO INSTALL A
B
ASE 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.
&',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.
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&', DO NOT take return air
from bathrooms, kitchens,
furnace rooms, garages, utility or
laundry rooms, or cold areas.
&',DO NOT use a rear air
return.
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.
!%('*,&,If a flexible duct
connector must be used, it
MUST
be rated for a minimum
temperature of 250°F
.
continuous.
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1. Position the unit to minimize long
r
uns 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
3@6@AFGE;@93@3;D
5A@6;F;A@;@9B>7@G? install the
special non-combustible floor
base. See Figure 10.
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/*&!&
JACKET
DRILL (2)
3/16" DIA.
HOLES
8.000
4.875
1.531