Carrier 58MXA Installation, Start-Up, And Operating Instructions Manual page 24

Table 5—Combustion-Air and Vent Pipe Termina-
tion Clearances
LOCATION
Above grade level or above
anticipated snow depth
Dryer/Water heater vent
From plumbing vent stack
From any mechanical fresh air intake
For furnaces with an input capacity of
100,000 Btuh or less—from any non-
mechanical air supply (windows or doors
which can be opened) or combustion-air
opening
For furnaces with an input capacity greater
than 100,000 Btuh or less—from any non-
mechanical air supply (windows or doors
which can be opened) or combustion-air
opening
From service regulator vent, electric and
gas meters and relief equipment
Above grade when adjacent to public
walkway
* Horizontal distance.
† 18 in. above roof surface in Canada.
NOTES:
1. If installing 2 adjacent 58MXA furnaces, refer to Multiventing and Vent
Terminations section for proper vent configurations.
2. When locating combustion-air and vent terminations, consideration must be
given to prevailing winds, location, and other conditions which may cause
recirculation of the appliance's own flue products or the flue products of
adjacent vents. Recirculation can cause poor combustion, inlet condensate
problems, and accelerated corrosion of heat exchangers.
3. Vent termination can not terminate less than 2 ft horizontal and 7 ft above
public walkway or where condensate vapor or droplets may be a hazard.
4. Vent termination must be at least 3 feet above any forced draft inlets within
10 feet horizontal. Vent termination must be at least 3 feet horizontal from
other direct vent appliances intake unless otherwise specified by manufac-
turer.
5. 3 ft radius of furnace air-intake terminal and 1 ft horizontally from vertical
centerline of furnace air-intake terminal.
6. Above a meter/regulator within 3 feet horizontally of vertical centerline of
meter/regulator vent outlet to a maximum vertacal distance of 15 feet.
Combustion air must not be taken from 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 fresheners, adhesives, paint, and
other household products. Locate combustion-air inlet as far
as possible from swimming pool and swimming pool pump
house.
Excessive exposure to contaminated combustion air will
result in safety and performance related problems.
Solvent cements are combustible. Keep away from heat,
sparks, and open flame. Use only in well-ventilated areas.
Avoid breathing in vapor or allowing contact with skin or
eyes. Failure to follow this warning could result in fire,
property damage, personal injury, or death.
All combustion-air and vent pipes must be airtight and
watertight. Pipes must also terminate exactly as shown in Fig.
36, 37, 38, 39, or 40. Failure to follow this warning could
result in property damage, personal injury, or death.
NOTE: The minimum combustion-air and vent pipe length (each)
for these furnaces is 5 ft. Short pipe lengths (5-8 ft) may discharge
water droplets. These droplets may be undesirable, and a 12-in.
minimum offset pipe section is recommended, as shown in Fig. 34,
to reduce excessive droplets from exiting vent pipe outlet.
CLEARANCE (FT)
Combustion-Air and Vent Pipe Diameter
U.S.A. Canada
Determine combustion-air and vent pipe diameter.
1 1†
1. Using Table 7, individually determine the combustion-air and
Note 5 Note 5
3 3
Note 4 6
2. When installing vent systems of short pipe length, use the
1 1
NOTE: Do not count elbows or pipe sections in terminations or
within furnace. See shaded areas in Fig. 36, 37, 38, 39, and 40.
1 3
3* Note 6
Note 3 Note 3
Combustion-Air and Vent Pipe Attachment
NOTE: All pipe joints must be watertight except attachment of
combustion-air pipe to inlet housing connection, since it may be
necessary to remove pipe for servicing.
1. Attach combustion-air pipe as follows:
NOTE: A 2-in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing.
NOTE: DO NOT OVERTIGHTEN SCREW. Breakage to intake
housing or fitting may cause air leakage to occur.
24
vent pipe diameters. Pick the larger of these 2 pipe diameters
and use this diameter for both combustion-air and vent pipes.
smallest allowable pipe diameter. Do not use pipe size greater
than required or incomplete combustion, flame disturbance, or
flame sense lockout may occur.
EXAMPLE: An 080-12 size furnace 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 combustion-air pipe. Table 7
indicates this application would allow a 2-in. diameter vent
pipe, but require a 2-1/2 in. diameter combustion air pipe
(2-in. pipe is good for 35 ft with 3 elbows, but only 30 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 installation were in Albuquerque, elevation 5250 ft
above sea level, installation would require 2-1/2 in. vent
pipe and combustion-air pipe. At 5001- to 6000-ft eleva-
tion, 2-in. pipe is only good for 17 ft with 5 elbows, and
2-1/2 in. pipe is good for 70 ft with 5 elbows.
a. Determine location of combustion-air intake pipe connec-
tion to combustion-air intake housing as shown in Fig. 33
for application.
b. Reposition combustion-air intake housing plug fitting in
appropriate unused intake housing connection.
c. If required, insert perforated disk assembly (factory-
supplied in loose parts bag) in intake housing where
combustion-air intake pipe will be connected. If half disk
set is required, install with shoulder of disk against stop in
combustion-air inlet.
d. Install pipe support (factory-supplied in loose parts bag)
into selected furnace casing combustion-air pipe hole. Pipe
support should be positioned at bottom of casing hole.
e. Insert 2-in. diameter pipe into intake housing.
f. Install casing hole filler cap (factory-supplied in loose parts
bag) in unused combustion-air pipe casing hold.
g. Drill a 1/8-in. hole in 2-in. combustion-air pipe using hole
in intake housing as a guide.
h. Install a field-supplied No. 6 or No. 8 sheet metal screw
into combustion-air pipe.