Carrier 58MVB Installation, Start-Up, And Operating Instructions Manual page 38

FURNACE
NOT IN
HORIZONTAL
SECTION
Fig. 40—Combustion-Air and Vent Pipe Diameter
Transition Location and Elbow Configuration
COMBUSTION – AIR
INTAKE HOUSING
3/8" ID TUBE
3/16"
DRILL
4"
MIN
TRAP
TO OPEN
DRAIN
Fig. 41—Intake Housing Plug Fitting Drain
The minimum vent pipe length for these furnaces is 5 ft. Short pipe
lengths (5-8 ft) may discharge condensate droplets. These conden-
sate droplets may be undesirable. A 12-in. minimum offset pipe
section is recommended to reduce excessive condensate droplets
from exiting vent pipe outlet. (See Fig. 42.)
Attachment of Vent Pipe
1. Determine vent pipe diameter and maximum pipe lengths
using Table 11.
NOTE: (Direct Vent/2-Pipe ONLY) vent pipe system has the
same diameter and same length as combustion air pipe as men-
tioned in section "Assembly of Combustion Air Pipe (Direct
Vent/2-Pipe system ONLY)."
NOTE: Do not count elbows or pipe sections in terminations or
within furnace (all elbows shown in Fig. 40 and Fig. 41 are not be
counted).
2. Determine location of vent pipe connection to inducer housing
as shown in Fig. 38 for application.
3. Reposition elastomeric (rubber) inducer housing outlet cap
and clamp to appropriate unused inducer housing connection.
Tighten clamp.
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
A93034
BURNER
BOX
COMBUSTION –
AIR PIPE
A93035
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit component
damage.
Inducer housing outlet cap must be installed and fully seated
against inducer housing. Clamp must be tightened to prevent
any condensate leakage.
4. Install combustion-air pipe grommet (factory-supplied in
loose parts bag) into selected furnace casing vent pipe hole.
(See Fig. 31.)
5. Be certain that mating surfaces of inducer housing connection
elastomeric (rubber) coupling, and 2-in. diameter vent pipe are
clean and dry. Assemble the elastomeric (rubber) vent cou-
pling (with 2 loose clamps) onto inducer housing connection.
Insert the 2-in. diameter vent pipe through the elastomeric
(rubber) coupling and fully into inducer housing connection
until it touches a stop inside the inducer housing outlet.
Tighten the screws on both clamps to 15-in-lb. of torque. pipe
to inducer housing. Tighten the clamp screws to 15 in.-lb. of
torque.
NOTE: Starting at furnace, slope vent pipe a minimum of 1/4-in.
per linear ft with no sags between hangers.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit component
damage.
Vent pipe must be installed and fully seated against inducer
housing internal stop. Clamp must be tightened to prevent any
condensate leakage.
6. Install casing hole filler cap (factory-supplied in loose parts
bag) in unused vent pipe casing hole.
Installation Guidelines for Combustion Air Pipe and Vent Pipe
It is recommended that all pipes be cut, prepared, and pre-
assembled before permanently cementing any joint.
1. Attach combustion air pipe and vent pipe per instructions in
sections "Combustion Air Pipe" and "Vent Pipe."
2. Working from furnace to outside, cut pipe to required
length(s).
3. Deburr inside and outside of pipe.
4. Chamfer outside edge of pipe for better distribution of primer
and cement.
5. Clean and dry all surfaces to be joined.
6. Check dry fit of pipe and mark insertion depth on pipe.
7. After pipes have been cut and preassembled, apply generous
layer of cement primer to pipe fitting socket and end of pipe
to insertion mark. Quickly apply approved cement to end of
pipe and fitting socket (over primer). Apply cement in a light,
uniform coat on inside of socket to prevent buildup of excess
cement. Apply second coat.
8. While cement is still wet, twist pipe into socket with 1/4 turn.
Be sure pipe is fully inserted into fitting socket.
9. Wipe excess cement from joint. A continuous bead of cement
will be visible around perimeter of a properly made joint.
10. Handle pipe joints carefully until cement sets.
11. Horizontal portions of the venting system shall be supportive
to prevent sagging support. Support combustion air piping (if
applicable) and vent piping a minimum of every 5 ft (3 ft for
SDR-21 or -26 PVC) using perforated metal hanging strap.
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