Combustion-Air And Vent Piping - Carrier 58MVP Installation, Start-Up, And Operating Instructions Manual

dampers, any other gas burning appliances to their previous
condition of use.
7. If improper venting is observed during any of above tests,
common vent system must be corrected. Vent system or vent
connectors may need to be resized. For any other appliances
when resizing vent systems or vent connectors, system or
connector must be sized to approach minimum size as
determined using appropriate table found in Part 11 of NFGC
or Section 5 of NSCNGPIC.
Step 2—Combustion-Air and Vent Piping
GENERAL
Combustion-air and vent pipe fittings must conform to American
National Standards Institute (ANSI) standards and American
Society for Testing and Materials (ASTM) standards D1785
(schedule-40 PVC), D2665 (PVC-DWV), D2241 (SDR-21 and
SDR-26 PVC), D2661 (ABS-DWV), F628 (schedule-40 ABS), or
F891 (PVC-DWV cellular core). Pipe cement and primer must
conform to ASTM standards D2564 (PVC) or D2235 (ABS). See
Table 5 for maximum pipe lengths and Fig. 31, 32, 33, 34, and 35
for exterior piping arrangements.
In Canada construct all combustion-air and vent pipes for this unit
of CSA or ULC certified schedule-40 PVC, PVC-DWV or
ABS-DWV pipe and pipe cement. SDR pipe is NOT approved in
Canada.
NOTE: Furnace combustion-air and vent pipe connections are
sized for 2-in. pipe. Any pipe size change should be made outside
furnace casing in vertical pipe. (See Fig. 27.) This allows proper
drainage of vent condensate.
Combustion-air and vent pipes must terminate together in same
atmosphere pressure zone, either through roof or sidewall (roof
termination preferred), using accessory termination kit. See Table
4 for required clearances.
Furnace combustion-air and vent pipe connections must be at-
tached as shown in Fig. 28. Combustion-air intake plug fitting and
inducer housing alternate vent cap may need to be relocated in
some applications.
FURNACE
NOT IN
HORIZONTAL
SECTION
Fig. 27—Combustion-Air and Vent Pipe Diameter
Transition Location and Elbow Configuration
When combustion-air pipe is installed above a suspended
ceiling, pipe must be insulated with 3/8-in. thick Armaflex-
type insulation. Combustion-air pipe should also be insulated
when it passes through warm, humid space.
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
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Table 4—Combustion-Air and Vent Pipe
Termination Clearances
LOCATION
Above grade level or above
anticipated snow depth
Dryer vent
From plumbing vent stack
From any mechanical fresh
air intake
For furnaces with an input
capacity less than 100,000
Btuh–from any non-
mechanical air supply (win-
dows or doors which can
be opened) or combustion-
air opening
For furnaces with an input
capacity greater than
100,000 Btuh–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 equip-
ment
Above grade when adjacent
to public walkway
* Horizontal distance.
† 18 in. above roof surface in Canada.
‡ 36 in. to electric meter in Canada only.
NOTES:
1. If installing 2 adjacent 58MVP 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.
Fig. 28—Combustion-Air and Vent Pipe
21
CLEARANCE (FT)
U.S.A. Canada
1
3
3
1
1
1
4*
7
Connections
1†
3
3
6
1
3
6‡
7
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