7. Gas Supply
and Piping
CARBON
MONOXIDE
POISONING,
FIRE
AND
EXPLOSION HAZARD.
Failure
to follow
safety
warnings
exactly
could
result
in death,
personal
injury
and/or
property
damage.
Models designated
for Natural Gas are to be used
with
Natural
Gas
ONLY,
unless
properly
converted
to use with LP gas.
Gas Supply Requirements
•
Use only the Type of gas approved
for this furnace.
See rating
plate for approved
gas type.
•
Gas input must not exceed
the rated input shown on the rating
plate.
Overfiring
will result
in failure
of heat
exchanger
and
cause dangerous
operation.
Do not allow minimum
supply
pressure
to vary downward.
Do-
ing so will decrease
input to furnace.
Refer to Table
3 for gas
supply.
Refer to Table
5 or Table
6 for manifold
pressures.
i
I
Pressures
Gas Type
Supply
Pressure
Recommended
Max.
Natural
7"
14"
Propane
11"
14"
Min,
4,5"
11"
Gas Piping Requirements
NOTE: The gas supply
line must be installed bya qualified service
technician
in accordance
with all building
codes.
NOTE:
In the state
of Massachusetts.
1,
2.
a.
Gas supply connections
MUST be performed
by a li-
censed plumber or gas fitter).
b.
When
flexible
connectors
are used, the maximum
length
shall
not exceed
36" (915 ram).
c.
When
lever handle
type manual
equipment
shutoff
valves
are used,
they shall be T-handle
valves.
d.
The use of copper tubing for gas piping is NOT approved.
Install gas piping in accordance
with local codes,
or in the ab-
sence
of local codes,
the applicable
national
codes.
It is recommended
that a manual
equipment
shutoff
valve be
installed
in the gas supply
line outside
the furnace.
Locate
valve as close to the furnace
as possible
where
it is readily
ac-
cessible.
Refer to Figure
7.
Typical Gas Piping ('8DNL)
Drip leg &
pipe cap _.
Listed Flexible
Gas Appliance
Connector if
11o4
IO]
Se_c%
union
\
Gas control
valve
Elbows &
25-25-17
short nipples
3.
Use black iron or steel pipe and fittings
or other pipe approved
by local code.
4.
Use pipe thread compound
which is resistant
to natural
and LP
gases.
5.
Use ground joint
unions
and install a drip leg no less than 3"
long to trap dirt and moisture
before
it can enter
gas control
valve
inside
furnace.
6.
Provide
a 118" NPT plugged
tapping
for test gauge
connection
immediately
up stream
of gas supply
connection
to furnace.
7.
Use two pipe wrenches
when making
connections
to prevent
gas valve
from turning.
NOTE:
If local codes allow the use of a flexible
gas appliance
con-
nector,
always
use a new listed connector.
Do not use a connector
which
has previously
served
another
gas appliance.
8.
Flexible
corrugated
metal gas connector
may NOT be used in-
side the furnace
or be secured
or supported
by the furnace
or
ductwork.
9.
Properly
size gas pipe to handle
combined
appliance
load or
run gas pipe directly
from gas meter
or LP gas regulator.
10. Install
correct
pipe size for run length
and furnace
rating.
11. Measure
pipe length
from gas meter or LP second
stage regu-
lator to determine
gas pipe size.
Left Side Gas Supply Piping
Gas line can be installed
directly
to the gas valve through
the hole
provided
in the left side of the cabinet.
See Figure
7
FIRE HAZARD
Failure
to follow
safety
warnings
exactly
could
result
in death,
personal
injury
and/or
property
damage.
Use wrench to hold furnace gas control
valve when
turning
elbows and gas line to prevent damage to the
gas control valve and furnace.
Right Side Gas Supply Piping
Two(2)
90 ° street
elbows
or two(2)
90 ° standard
elbows
and
two(2)
close
nipples
are required
for right
side gas supply.
See
Figure
7.
Piping with Street Elbows
1.
Assemble
the elbows
so that the outlet of one(l)
elbow
is 90 °
from the inlet of the other. The elbows
should
be tight enough
to be leak proof.
An additional
1/4 turn will be required
at the
end of step
2, see Figure
8.
_]
441 01 2314 02
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