Service Manual
21
DUCT CONNECTIONS
Return duct must not be connected to the back of any fur-
nace. Up flow furnaces installed vertically may have return
air duct connections on either side or the furnace bottom.
When airflow requirements are greater than 1,800 CFM for
heating or cooling, both sides or a bottom return must be
used.
Down flow furnaces installed vertically must have the re-
turn duct connection on top the furnace. For any furnace
installed horizontally, return duct must be attached to the
end of the furnace.
Recommended Installation Positions
Propane Gas/High Altitude Installations
WARNING
P
OSSIBLE
PROPERTY
DAMAGE
,
PERSONAL
INJURY
OR
DEATH
MAY
OCCUR
IF
THE
CORRECT
CONVERSION
KITS
ARE
NOT
INSTALLED
. T
HE
APPROPRIATE
KITS
MUST
BE
APPLIED
TO
ENSURE
SAFE
AND
PROPER
FURNACE
OPERATION
. A
LL
CONVERSIONS
MUST
BE
PERFORMED
BY
A
QUALIFIED
INSTALLER
OR
SERVICE
AGENCY
.
This furnace is shipped from the factory configured for natural
gas up to 10,000 ft. altitude. Propane conversions require
the proper LP kit to compensate for the energy content dif-
ference between natural and propane gas.
LP kits include an L.P. gas valve and a set of gas orifices.
Do not change or adjust the gas valve regulator springs.
High
Stage
Low
Stage
Natural None #45
1
3.5" w.c. 1" w.c. None
Propane LPM-09 1.25MM
2
10.0" w.c. 2.6" w.c. No ne
M anifold P ressure P ressure
Switch
Change
0-10,000
NOTE: In Canada, gas furnaces are only certified to 4500 feet.
Gas Altitude Kit Orifice
Vent/Flue Pipe & Combustion Air Pipe
F
AILURE
TO
FOLLOW
THESE
INSTRUCTIONS
CAN
RESULT
IN
BODILY
INJURY
OR
DEATH
. C
AREFULLY
READ
AND
FOLLOW
ALL
INSTRUCTIONS
GIVEN
IN
THIS
SECTION
.
WARNING
PROPER VENT/FLUE AND COMBUSTION AIR PIPING PRACTICES
Adhere to these instructions to ensure safe and proper furnace
performance. The length, diameter, and number of elbows of
the vent/flue pipe and combustion air pipe (when applicable)
affects the performance of the furnace and must be carefully
sized. All piping must be installed in accordance with local codes
and the insttaltion manual shipped with the furnace.
Piping must be adequately secured and supported to prohibit
sagging, joint separation, and/or detachment from the fur-
nace. Horizontal runs of vent/flue piping must be supported
every three to five feet and must maintain a 1/4 inch per foot
downward slope, back towards the furnace, to properly return
condensate to the furnace’s drain system.
PRODUCT DESIGN