Carrier Aero 39MN Series Installation, Start-Up And Service Instructions Manual page 172

• Do not locate unit in areas where corrosive vapors (such
as chlorinated, halogenated, or acidic vapors) are present
in the atmosphere or can be mixed with combustion air
entering heater.
Clearance Requirements for Outdoor Installations —
serve the following additional requirements for outdoor instal-
lations:
• Provide at least 6 feet clearance to side of the unit, where
the combustion air inlet or vent (flue) gas discharge is
located, from walls, parapets or adjacent buildings or
equipment.
• Unit must be installed with combustion air openings
located at least one (1) ft above the average snow depth
for the location.
• Do not locate unit near building ventilators or exhausts,
or areas where corrosive chemical vapors can be drawn
into combustion air supply.
• Do not install units in locations where flue products can
be drawn in the adjacent building openings such as win-
dows, fresh air intakes, etc.
• Be sure that vent discharge for flue gases is directed
away from combustion air inlet and located to prevent
flue products from being drawn into combustion air sup-
ply. Burner performance can be adversely affected by
recirculation of flue products.
• Combustion air inlet and flue gas outlet must be located
in the same pressure zone to minimize effects of wind on
burner and heater performance.
Clearance Requirements for Indoor Installations —
serve the following additional requirements for indoor installa-
tions:
• Locate unit to ensure an adequate supply of fresh air to
replace air used in the combustion and ventilation pro-
cess.
• When locating units, it is important to consider that
exhaust vent piping must connected to the outside atmo-
sphere. Location should minimize the number of elbows
or turns in vent piping.
GAS SUPPLY, PIPING, AND CONNECTIONS — Instal-
lation of piping must conform with local building codes and or-
dinances, or in the absence of local codes with ANSI Z223.1,
the National Fuel Gas Code. In Canada, installation must be in
accordance with CAN/CGA-B149.1 for natural gas and
B149.2 for propane units.
Use a pipe sealant resistant to LP gases on gas supply con-
nections to heater. Gas piping must be sized for the total Btu in-
put of all furnaces or units serviced by a single supply.
Properly support gas valve with back-up wrench during
supply pipe installation to prevent loosening valve or damage
to burner assembly or manifold.
Gas piping must be sized for the total Btu input of all units
(heaters) serviced by a single supply. A 2-in. NPT main gas
header is provided as standard.
A service regulator must be provided to provide gas to the
heater assembly at the proper pressure. Verify that the regulator
installed is sized and properly orificed for total input of all
heaters.
A drip leg (sediment trap) and a manual shut-off valve must
be provided immediately upstream of the gas control on the
heating unit. To facilitate servicing of unit, installation of a
union is recommended. See Fig. 141.
Individual furnaces require a minimum inlet gas pressure as
shown in Table 41.
IMPORTANT: Gas pressure to appliance controls must
never exceed 13.5 in. wg ( / psig).
1
2
Pressure Testing — A
side of the gas valve to the heater. See Fig. 142-144. A fitting
suitable for connection to a pressure gage capable of measuring
gas pressure should be connected to each heater serviced by a
single regulator so that gas pressure at each heater can be mea-
Ob-
sured with all heaters in operation.
IMPORTANT: When pressure testing at
less, close the manual shut-off valve on the appliance
before testing. When pressure testing the gas supply
line at 1 / psig or greater, close the manual shut-off
2
valve and disconnect the heater from supply line to be
tested. Cap or plug the supply line.
All field gas piping must be pressure and leak-tested
prior to operation. Never use an open flame to check for
leaks. Personal injury may result. Use a soap solution or
other leak detecting solution.
Pressure/leak test all connections prior to putting unit in ser-
vice. The furnace gas piping was leak-tested prior to shipping.
However, during shipping and installation connections may
have loosened. Check for leaks using a soap solution and cor-
rect any leaks before placing furnace in operation.
VENTING — Gas furnaces must be connected to a properly
designed venting system to convey flue gases away from the
Ob-
heating system or outside of the heated space. See the section
Installation Requirements on page 169 for reference to applica-
ble codes and standards. The rack assembly requires a special
venting system.
Venting for Outdoor Installations — For outdoor applica-
tions, a vent riser kit is available. See Fig. 147. In outdoor in-
stallations where the flue riser kit is not used, the venting sys-
tem must be properly designed for the specific application by a
manufacturer/provider of the listed type of venting systems.
The connection from furnace-induced draft fans to round vent
pipe requires custom adapters to ensure leak-free joints. Con-
tact a venting system manufacturer for availability, if the vent-
ing system was not included with the heating system.
18" MIN ABOVE
TOP OF AHU
CABINET
Fig. 147 — Outdoor Venting with Flue Riser Kit
172
/ in. NPT tap is provided on the inlet
1
8
1 /
2
WARNING
COMBUSTION
AIR INTAKE
LOUVERS
OPTIONAL
FLUE
RISER
psig or