Upflow; Downflow - Carrier 58MCB Installation, Start-Up, And Operating Instructions Manual

NOTE: Select 1 vent pipe connection and
1 combustion-air pipe connection.
AIR
FLOW
COMBUSTION- COMBUSTION-
AIR AIR
VENT
*

UPFLOW

COMBUSTION-
AIR
VENT
**
AIR
FLOW
†
HORIZONTAL-LEFT DISCHARGE
* For Non-Direct Vent (1-Pipe) system, orient elbow so that its
opening faces down.
** For Non-Direct Vent (1-Pipe) system, orient elbow so that its
opening faces sideways.
† An external trap kit (see furnace product data sheet) must be used.
→
Fig. 35—Combustion-Air and Vent Pipe
Connections
Assembly of Combustion Air Pipe (Non-Direct Vent/1-Pipe
System ONLY)
1. Permanently install perforated disk assembly (factory-
supplied in loose parts bag) in combustion-air elbow using
RTV or by cementing, as shown in Fig. 36. For 120,000 Btuh
size units only: separate the 2 halves of perforated disk
assembly and use only the shouldered disk half.
2. Determine the length of straight portion of combustion-air
inlet pipe from Fig. 36.
3. Cut field-supplied 2-in. diameter PVC pipe to length as
determined per Fig. 36.
4. Permanently attach elbow/perforated disk assembly to straight
portion of pipe using RTV or by cementing as shown in Fig.
36.
Assembly of Combustion Air Pipe (Direct Vent-2-Pipe
System ONLY)
1. Using Table 11, determine the smallest combustion air diam-
eter permitted. Pick the larger diameter and use it for both
combustion and vent pipe.
NOTE: Do not count elbows or pipe sections in terminations or
within furnace (All elblows shown in Fig. 40 and Fig. 41 are not
to be counted).
NOTE: Select 1 vent pipe connection and
1 combustion-air pipe connection.
VENT
VENT
VENT
COMBUSTION- COMBUSTION-
AIR AIR
AIR
FLOW

DOWNFLOW

COMBUSTION-
AIR
VENT
**
†
HORIZONTAL-RIGHT DISCHARGE
*
COMBUSTION-AIR DISC
(FACTORY-SUPPLIED IN
LOOSE PARTS BAG)
Length of Straight Pipe Portion of
Combustion-Air Inlet Pipe Assembly (In.)
AIR
CASING WIDTH
FLOW
Fig. 36—Combustion-Air Inlet Pipe Assembly
UNIT MAY NOT OPERATE
Failure to follow this caution may result in incomplete
combusiton, flame disturbance, or flame sense lockout.
When installing combusiton air and vent system of short pipe
length, the smallest allowable pipe diameter must be used.
NOTE: A 2-in. diameter pipe must be used within furnace casing.
A05092
Make all pipe diameter transitions outside furnacec casing per Fig.
37.
2. If required per Table 11, insert perforated disk assembly
(factory-supplied in loose parts bag) in intake housing where
combustion air pipe will be connected. If half disk set is
required, install only shouldered disk half.
Attachment of Combustion Air Pipe
1. Determine location of combustion air intake pipe connection
to combustion air intake housing as shown in Fig. 35 for
application.
2. Reposition combustion air intake housing plug fitting in
appropriate unused intake housing connection.
3. 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.
4. Insert assembled combustion air inlet pipe into intake housing
as shown in Fig. 35.
5. Drill a 1/8-in. hole in 2-in, combustion air pipe using the hole
in intake housing as a guide.
6. Install a field-supplied No. 6 or No. 8 sheet metal screw into
combustion air pipe.
7. Install casing hole filler cap (factory-supplied in loose parts
bag) in unused combustion air pipe casing hole.
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 igniter or flame sensor.
33
FIELD-SUPPLIED
2-IN. DIAMETER
FIELD-SUPPLIED
PVC 90° ELBOW
2-IN. DIAMETER
PVC PIPE
A
17-1/2
10-1/2 ± 1/2
21
24-1/2
A96211
A
8-1/2 ± 1/2
12 ± 1/2