Carrier 58MXA Installation, Start-Up, And Operating Instructions Manual page 25

(
NOT IN
HORIZONTAL
SECTION
FURNACE
TRANSITION IN
VERTICAL SECTION
A93034
Fig. 32--CombustionoAir and Vent Pipe Diameter
Transition Location and Elbow Configuration
FIRE AND EXPLOSION HAZARD
Failure to follow this warning could result in fire, property
damage, personal injury, or death.
Solvent cements are combustible. Keep away h'om heat,
sparks, and open flame. Use only in well-ventilated areas.
Avoid breathing in vapor or allowing contact with skin or
eyes.
CARBON MONOXIDE/PROPERTY DAMAGE
Failure to follow this warning could result in property
damage, personal injury, or death.
All combustion-air and vent pipes must be airtight and
watertight Pipes must also tem_inate exactly as shown in Fig.
36, 37, 38, 39, or 40.
PROPERTY DAMAGE
Failure to %llow this caution may result in dripping condeno
sate and potential property damage.
When combustion-air pipe is installed above a suspended
ceiling, pipe must be insulated with 3/8oin. thick Armaflexo
type insulation. ( ombustionoair pipe should also be insulated
when it passes through wam_, humid space
An abandoned masonry chimney may be used as a raceway %r
properly insulated and supported combustionoair and vent pipes.
Eacia fhrnace must have its own set of combustion-air and vent
pipes and be terminated individually, as shown in Fig. 42.
Other gas appliances with their own venting system may also use
the abandoned chimney as a raceway providing it is permitted by
local code, the NFGC or NSCNGPIC, and the vent or liner
manufacturer's installation instn/ctions (?are must be taken to
prevent the exhaust gases ti'om one appliance fiom contaminating
the combustion air of other gas appliances.
UNIT MAY NOT OPERATE
Failure to follow this caution may result in intem_ittent unit
operation.
When vent pipe is exposed to temperatures below fi'eezing,
such as when it passes through an unheated space or when a
chimney is used as a raceway, pipe must be insulated as
shown in Table 8 with Armaflexotype insulation
UNIT CORROSION HAZARD
Excessive exposure to contaminated comhustion air may
result in sa_bty and perfbrrnance related problems.
Combustion air must not be taken fiom inside structure
because inside air is frequently contaminated by halogens,
which include fluorides, chlorides, bromides, and iodides.
These elements are found in aerosols, detergents, bleaches,
cleaning solvents, salts, air fi'esheners, adhesives, paint, and
other household products. Locate combustionoair inlet as _r
as possible fi'om swimming pool and swimming pool pump
hol.lSe,
NOTE: The minimum combustionoair and vent pipe length (each)
for d-_ese hlmaces is 5 ft. Short pipe lengths (5°8 ft) may discharge
water droplets These &oplets may be undesirable, and a 12-in.
minimum off'set pipe section is recommended, as shown in Fig. 34,
to reduce excessive droplets f_'om exiting vent pipe outlet.
Combustion-Air and Vent Pipe Diameter
Determine combustion-air and vent pipe diameter.
1. Using Table 7, individually determine the smallest
combustionoair and vent pipe diameters permitted for each
pipe. Pick the larger of these 2 pipe diameters and use this
diameter for both combustionoair and vent pipes.
2. When installing vent systems of short pipe length, use the
smallest allowable pipe diameter. Do not use pipe size greater
than required becuase incomplete combustion, flame distur-
bance, or flame sense lockout may occur.
NOTE: Do not count elbows or pipe sections in terminations or
within h_mace. See shaded areas in Fig. 36, 37, 38, 39, and 40.
EXAMPLE: An 080-12 size _hrnace located in Indianapo-
lis, elevation 650 ft above sea level, could be installed in an
application requiring 3 elbows and 32 ft of vent pipe, along
with 5 elbows and 34 ft of cornhustionoair pipe Table 7
indicates this application wo_dd allow a 2oin. diameter vent
pipe, but require a 2ol/2 in diameter combustion air pipe
(2oin. pipe is good fbr 35 ft with 3 elbows, but only 30 ft
with 5 elbows). Therelbre, 2-1/2 in diameter pipe must be
used for both vent and combustion-air pipes since larger
required diameter must always be used for both pipes. If
same installation were in Albuquerque, elevation 5250 _
above sea level, installation would require 2ol/2 in. vent
pipe and combustion-air pipe. At 5001o to 6000o_t eleva-
tion, 2-in. pipe is only good for 17 R with 5 elbows, and
2-1/2 in. pipe is good fbr 70 R with 5 elbows.
(ombustion-Air and Vent Pipe Attachment
NOTE: All pipe joints must be cemented except attachment of
combustion-air pipe to inlet housing connection, since it may be
necessary to remove pipe _br servicing.
1. Attach combustion=air pipe as follows:
a. Determine location of combustion-air intake pipe connec-
tion to combustion-air intake housing as shown in Fig. 33
for application.
b. Reposition combustionoair intake housing plug fitting in
appropriate unused intake housing connection.
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