Carrier 58MXA Installation, Start-Up, And Operating Instructions Manual page 31

VERTICAL SEPARATION
BETWEEN COMBUSTION
CLEARANCE ABOVE HIGHEST
ANTICIPATED SNOW LEVEL.
MAXIMUM OF 24 IN. ABOVE ROOF.
NOTE: Shaded parts in Fig. 36, 37, 38, 39, and 40 are considered
to be termination. These components should NOT be counted
when determining pipe diameter. Roof termination is preferred
since it is less susceptible to damage, has reduced chances to take
in contaminants, and has less visible vent vapors. (See Fig. 36 or
37.) Sidewall termination may require sealing or shielding of
building surfaces with a corrosive resistance material due to
corrosive combustion products of vent system.
Extended Exposed Sidewall Pipes
Sidewall combustion-air and vent pipe terminations may be
extended beyond area shown in Fig. 39 or 40 in outside ambient by
insulating pipes as indicated in Table 8.
1. Determine combustion-air and vent pipe diameters, as stated
above, using total pipe length and number of elbows.
2. Using winter design temperature (used in load calculations),
find appropriate temperature for your application and furnace
model.
3. Determine required insulation thickness for exposed pipe
lengths.
NOTE: Pipe length (ft) specified for maximum pipe lengths
located in unconditioned spaces. Pipes located in unconditioned
space cannot exceed total allowable pipe length as specified in
Table 7.
Two-Pipe Termination Kit
1. Determine location for termination.
Consider the following when determining an appropriate
location for termination kit.
a. Comply with all clearance requirements as stated in Table
5.
b. Termination kit should be positioned where vent vapors
will not damage plants/shrubs or air conditioning equip-
ment.
c. Termination kit should be positioned so that it will not be
affected by wind eddy (such as inside building corners) or
allow recirculation of flue gases, airborne leaves, or light
snow.
d. Termination kit should be positioned where it will not be
damaged by or subjected to foreign objects, such as stones,
balls, etc.
COUPLING
AIR AND VENT
8 3 / 4 " FOR 3" KIT
6 3 / 4 " FOR 2" KIT
MAINTAIN 12 IN. MINIMUM
Fig. 36—Roof Termination (Preferred)
ROOF
18" MAXIMUM
BRACKET
VENT
e. Termination kit should be positioned where vent vapors are
not objectionable.
2. Cut 2 holes, 1 for each pipe, of appropriate size for pipe size
being used.
3. Loosely install elbow in bracket and place assembly on
combustion-air pipe.
Roof terminations—Loosely install pipe coupling on prop-
erly cut vent pipe. Coupling must be positioned so bracket will
mount as shown in Fig. 36.
For applications using combustion-air pipe option, indicated
by dashed lines in Fig. 36, install 90° street elbow into 90°
elbow, making U-fitting. A 180° U-fitting may be used.
Sidewall terminations—Install bracket as shown in Fig. 39 or
40.
For applications using vent pipe option indicated by dashed
lines in Fig. 39, rotate vent elbow 90° from position shown in
Fig. 39.
4. Disassemble loose pipe fittings. Clean and cement using same
procedures as used for system piping.
5. Check required dimensions as shown in Fig. 36, 39, or 40.
MAINTAIN 12 IN.
(18 IN. FOR CANADA)
MINIMUM CLEARANCE
ABOVE HIGHEST
ANTICIPATED SNOW
LEVEL. MAXIMUM OF
24 IN. ABOVE ROOF.
Fig. 37—Concentric Vent and Combustion-Air Roof
Termination (Preferred)
31
COMBUSTION
AIR
VENT
COMBUSTION
AIR
A87224
A93054