Carrier 58MVB Installation, Start-Up, And Operating Instructions Manual page 34

Table 10—Maximum Allowable Exposed Vent Pipe Length (Ft) With Insulation in Winter Design
WINTER DESIGN
UNIT
TEMPERATURE
SIZE
040-14
060-14
080-14
080-20
100-20
120-20
* 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 11.
† Insulation thickness based on R value of 3.5 per in.
FIELD-SUPPLIED
2-IN. DIAMETER
PVC 90 ELBOW
COMBUSTION-AIR DISC LOCATION-NON DIRECT
VENT/1-PIPE SYSTEM (FACTORY-SUPPLIED IN
LOOSE PARTS BAG)
Length of Straight Pipe Portion of
Combustion-Air Inlet Pipe Assembly (In.)
CASING WIDTH
17-1/2
21
24-1/2
→
Fig. 39—Combustion-Air Inlet Pipe Assembly
2. Reposition combustion air intake housing plug fitting in
appropriate unused intake housing connection.
3. Install combustion-air pipe grommet (factory-supplied in
loose parts bag) into selected furnace casing combustion-air
pipe hole.
4. Insert assembled combustion air inlet pipe into intake housing
as shown in Fig. 38.
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.
Temperature Ambient*
MAXIMUM PIPE
DIAMETER
(°F) (IN.)
20 2
0 2
-20 2
20 2
0 2
-20 2
20 2
0 2
-20 2
20 2-1/2
0 2-1/2
-20 2-1/2
20 3
0 3
-20 3
FIELD-SUPPLIED
2-IN. DIAMETER
PVC PIPE
A
A
8-1/2 ± 1/2
10-1/2 ± 1/2
12 ± 1/2
INSULATION THICKNESS (IN.)†
0 3/8
21
10
5
30
16
9
37
20
11
41
21
11
49
26
15
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.
Attachment of Combustion Air Intake Housing Plug Fitting
The combustion-air intake plug fitting must be installed in unused
combustion air intake housing. This fitting must be attached by
using RTV sealant, or by drilling a 1/8-in. hole in fitting, using
hole in intake housing as a guide. Install a field-supplied No. 6 or
No. 8 sheet metal screw.
NOTE: DO NOT OVERTIGHTEN SCREW. Breakage of intake
housing or fitting may cause air leakage to occur.
A plugged drain connection has been provided on this fitting for
use when moisture is found in combustion air intake pipe and
combustion box. If use of this drain connection is desired, drill out
fitting's tap plug with 3/16-in. drill and connect a field-supplied
A05122
3/8-in. tube. This tube should be routed to open condensate drain
for furnace and A/C (if used), and should be trapped, as shown in
Fig. 41.
NOTE: (Direct Vent/2-Pipe System ONLY). Moisture in com-
bustion air intake may be a result of improper termination. Ensure
combustion air pipe termination is similar to those as shown in Fig.
43 so that it will not be susceptible to area where light snow or
others sources of moisture could be pulled in.
→
VENT PIPE
General
Furnace vent connection must be attached as shown in Fig. 38.
CARBON MONOXIDE POISONING AND PROPERTY
DAMAGE HAZARD
Failure to follow this warning could result in property
damage, personal injury, or death.
Vent pipes must be airtight.
NOTE: A 2-in. diameter pipe must be used within the furnace
casing. Make all pipe diameter transitions outside furnace casing
per Fig. 40.
34
1/2 3/4
37 42 50
22 25 30
14 17 21
55 61 70
33 38 46
23 26 33
65 70 70
39 45 55
27 31 39
70 70 70
42 48 59
28 33 41
70 70 70
51 58 70
35 40 50
1
57
35
25
70
53
38
70
63
45
70
68
49
70
70
59