Carrier 58UVB series Installation, Start-Up, And Operating Instructions Manual page 20

NOTE: A 2- -in. diameter pipe must be used within furnace
casing. Make all pipe diameter transitions outside furnace casing.
(See Fig. 24).
CAUTION
!
UNIT MAY NOT OPERATE
Failure to follow this caution may result in incomplete
combustion, flame disturbance, or flame sense lockout.
When installing combustion air and vent system of short
pipe length, the smallest allowable pipe diameter must be
used.
CAUTION
!
UNIT CORROSION HAZARD
Excessive exposure to contaminated combustion air may
result in safety and performance related problems.
Combustion air must not be taken from inside structure
because that 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 fresheners, adhesives, paint, and
other household products. Locate combustion- -air inlet as
far as possible from swimming pool and swimming pool
pump house.
EXAMPLE:
An 100,000 BTUH furnace located in Indianapolis,
elevation 650 ft above sea level, could be installed as
either a direct vent/2- -pipe system that requires 3 elbows
and 28 ft of vent pipe, along with 5 elbows and 34 ft of
combustion- -air pipe. Table 8 indicates this application
would allow a 2- -in. diameter vent pipe, but require a
2- -1/2 in. diameter combustion air pipe. According to
Table 8, 2- -in. diameter pipe is good for 35 ft with 3
elbows, but only 25 ft with 5 elbows. Therefore, 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 installations were in Albuquerque, elevation
5250 ft above sea level:
Table 8 indicates that 2- -1/2 in. diameter vent pipe and
combustion- -air pipe are required.
If same applications are to be installed at 5001- - to 6000
ft elevation:
2- -in. pipe is only good for 23 ft (with 3 elbows) and 13
ft (with 5 elbows). Therefore, 2- -1/2 in. diameter
combustion air and vent pipe must be used.
COMBUSTION AIR PIPE
General
Furnace combustion- -air connection must be attached as shown in
Fig. 25. Combustion- -air intake housing plug may need to be
relocated in some applications.
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 for servicing.
NOTE: A 2- -in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing.
(See Fig. 24).
NOTE: Select 1 vent pipe connection and
1 combustion-air pipe connection.
COMBUSTION-
AIR
VENT
Fig. 25 --- Combustion Air and Vent Pipe Connections
Attachment of Combustion Air Pipe
NOTE: Combustion air pipe system has the same diameter and
same length as the vent pipe as mentioned in section
"Combustion- -Air and Vent Pipe Diameter."
1. Determine location of combustion- -air intake pipe
connection to combustion- -air intake housing as shown in
Fig. 25.
2. Verify combustion- -air intake housing plug fitting is
installed in appropriate unused intake housing connection.
3. Install combustion- -air pipe grommet (factory- -supplied in
loose parts bag)
combustion- -air pipe hole.
4. Determine the number of combustion air disk halves to be
installed in the combustion air intake housing. Insert
perforated disk half or assembly (factory supplied in loose
parts bag) in intake housing where combustion- -air intake
pipe will be connected.
5. Insert assembled combustion air inlet pipe into intake
housing as shown in Fig. 25.
NOTE: Do not cement combustion air intake pipe permanently
to combustion air intake housing since it may be necessary to
remove pipe for service of igniter or flame sensor.
6. Drill a 1/8- -in. hole in 2- -in, combustion air pipe using the
hole in intake housing as a guide.
7. Install a field- -supplied No. 6 or No. 8 sheet metal screw
into combustion air pipe.
8. Install casing hole filler cap (factory- -supplied in loose
parts bag) in unused combustion air pipe casing hole.
COMBUSTION AIR
INTAKE HOUSING
3/8" ID TUBE
3/16"
DRILL
4"
MIN
TRAP
TO OPEN
DRAIN
Fig. 26 --- Intake Housing Plug Fitting Drain
20
AIR
FLOW
COMBUSTION-
AIR
VENT
UPFLOW
A06500
into selected furnace casing
BURNER
BOX
COMBUSTION
AIR PIPE
A93035