Combustion Air Supply - Carrier AERO 39MN Installation, Start-Up And Service Instructions Manual

• Do not install units in locations where flue products can be
drawn in the adjacent building openings such as windows,
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 supply. Burner perfor-
mance 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.
Indoor Installations — Observe the following additional re-
quirements for indoor installations:
• Locate unit to ensure an adequate supply of fresh air to
replace air used in the combustion and ventilation process.
• When locating units, it is important to consider the exhaust
vent piping must connected to the outside atmosphere. Loca-
tion should minimize the number of elbows or turns in vent
pipe.
VENTING — Gas furnaces must be connected to a properly de-
signed venting system to convey flue gases away from the heat-
ing system or outside of the heated space. See the section Instal-
lation Requirements on page 118 for reference to applicable
codes and standards. The rack assembly requires a special vent-
ing system. For outdoor applications, a vent riser kit is available.
See Fig. 104.
18" MIN ABOVE
TOP OF AHU
CABINET
Fig. 104 — Outdoor Venting with Flue Riser Kit
For outdoor installations where the flue riser kit is not used,
and for all indoor installations, the venting system must be prop-
erly designed for the specific application by a manufacturer/pro-
vider of listed type venting systems. Connection from furnace in-
duced-draft fans to round vent pipe requires custom adapters to
ensure leak-free joints. Contact the venting system manufacturer
for part numbers and availability if the venting system was not
included with the heating system. See Fig. 105 for an example.
GAS SUPPLY, PIPING, AND CONNECTIONS — Installa-
tion of piping must conform with local building codes and ordi-
nances, or in the absence of local codes with ANSI Z223.1, the
National Fuel Gas Code. In Canada, installation must be in ac-
cordance with CAN/CGA-B149.1 for natural gas and B149.2 for
propane units.
a39-4402
COMBUSTION
AIR INTAKE
LOUVERS
OPTIONAL
FLUE
RISER
120
a39-4400
Fig. 105 — Indoor Venting with Flue Riser Kit
Use a pipe sealant resistant to LP gases on gas supply connec-
tions to heater. Gas piping must be sized for the total Btu input of
all furnaces or units serviced by a single supply.
Properly support gas valve with back-up wrench during sup-
ply 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 heat-
ing unit. To facilitate servicing of unit, installation of a union is
recommended. See Fig. 101 on page 117.
Individual furnaces require a minimum inlet gas pressure as
shown in Table 32 on page 116.
IMPORTANT: Gas pressure to appliance controls
must never exceed 13.5 in. wg (
Pressure Testing — A 1 / in. NPT tap is provided on the inlet
8
side of the gas valve to the heater. See Fig. 102A-102C on
page 117. A fitting suitable for connection to a pressure gage ca-
pable of measuring gas pressure should be connected to each
heater serviced by a single regulator so that gas pressure at each
heater can be measured 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.
COMBUSTION
AIR INTAKE
LOUVERS
OPTIONAL
VENT KIT
1 / psig).
2
/ psig or
1
2