Carrier 58MCA Installation, Start-Up, And Operating Instructions Manual page 22

VENT PIPE
HORIZONTAL TO ROOF
COMBUSTION-AIR PIPE
VERTICAL TO ROOF
b. Reposition combustion-air intake housing plug fitting in
appropriate unused intake housing connection.
c. Insert perforated disk assembly (factory supplied) in intake
housing where combustion-air intake pipe will be con-
nected.
d. Install pipe support (factory supplied in loose parts bag)
into selected furnace casing combustion-air pipe hole. Pipe
support should be positioned to bottom of casing hole.
e. Insert 2-in. diameter pipe into intake housing.
NOTE: A 2-in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing.
f. Drill a 1/8-in. hole in 2-in. combustion-air pipe using hole
in intake housing as a guide.
g. Install a field-supplied No. 6 or No. 8 sheet metal screw
into combustion-air pipe.
NOTE: DO NOT OVERTIGHTEN SCREW. Breakage to intake
housing or fitting may cause air leakage to occur.
NOTE: Do not attach combustion-air intake pipe permanently to
combustion-air intake housing since it may be necessary to remove
pipe for service of ignitor or flame sensor.
COMBUSTION-AIR INTAKE HOUSING PLUG
FITTING
12 " MIN
COMBUSTION-AIR PIPE
12 " MIN
NOTE: A 12 In. minimum horizontal pipe section is recommended with
short (5 to 8 ft) vent systems. This recommendation is to reduce
excessive condensate droplets from exiting the vent pipe.
Fig. 29—Short Vent (5 to 8 Ft) System
VENT PIPE
HORIZONTAL TO SIDEWALL
COMBUSTION-AIR PIPE
VENT PIPE
VERTICAL TO SIDEWALL
The combustion-air intake plug fitting must be installed in
unused combustion-air intake housing. This fitting must be
attached by using RTV sealant, or by drilling a 1/8-in. hole in
fitting, using hole in intake housing as a guide. Install a
field-supplied No. 6 or No. 8 sheet metal screw.
NOTE: DO NOT OVERTIGHTEN SCREW. Breakage to intake
housing or fitting may cause air leakage to occur.
A plugged drain connection has been provided on this fitting
for use when moisture is found in combustion-air intake pipe
and combustion box.
NOTE: Moisture in combustion-air intake may be result of
improper termination. Ensure combustion-air intake pipe is similar
to that shown in Fig. 31, 32, 33, 34, or 35 so it will not be
susceptible to areas where light snow or other sources of moisture
could be pulled in.
If use of this drain connection is desired, drill out fitting's tap
plug with a 3/16-in. drill and connect a field-supplied 3/8-in.
tube. This tube should be routed to open condensate drain for
furnace and A/C (if used), and should be trapped. (See Fig.
30.)
2. Attach vent pipe as follows:
a. Determine location of vent pipe connection to inducer
housing as shown in Fig. 28 for application.
22
12 " MIN
COMBUSTION-AIR PIPE
12 " MIN
VENT PIPE
A93591