Carrier 58MCA Installation, Start-Up, And Operating Instructions Manual page 22

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),
F891 (PVC-DWV cellular core) or F441 (schedule-40 CPVC pipe)
and F438 (schedule-40 CPVC fittings). Pipe cement and primer
must conform to ASTM standards D2564 or F493 (PVC or CPVC)
or D2235 (ABS). See Table 6 for maximum pipe lengths and Fig.
30, 31, 32, 33, and 34 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. 26.) This allows proper
drainage of vent condensate.
FURNACE
NOT IN
HORIZONTAL
SECTION
Fig. 26—Combustion-Air and Vent Pipe Diameter
Transition Location and Elbow Configuration
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
5 for required clearances.
Furnace combustion-air and vent pipe connections must be at-
tached as shown in Fig. 27. Combustion-air intake plug fitting and
inducer housing alternate vent cap may need to be relocated in
some applications.
NOTE: Slope combustion-air and vent pipes a minimum of 1/4
in. per linear ft with no sags between hangers.
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.
When vent pipe is exposed to temperatures below freezing,
such as when it passes through an unheated space or when a
chimney is used as a raceway, pipe must be insulated as
shown in Table 7 with Armaflex-type insulation.
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
A93034
Table 5—Combustion-Air and Vent Pipe
Termination Clearances
LOCATION
Above grade level or above antici-
pated 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 (windows or
doors which can be opened) or
combustion-air opening
From service regulator vent, electric
and gas meters, and relief equipment
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 58MCA Furnaces, refer to Multivent-
ing and Vent Terminations section for proper vent configura-
tions.
2. When locating combustion-air and vent terminations, consid-
eration 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.
3. Vent termination cannot terminate less than 2 ft horizontal and
7 ft above public walkway or where condensate vapor or
droplets may be a hazard.
Combustion air must not be taken from inside structure
because inside air is frequently contaminated by halogens,
which include fluorides, chlorides, bromides, and iodides.
These elements are found in aerosols, detergents, bleaches,
cleaning solvents, salts, air fresheners, adhesives, paint, and
other household products. Locate combustion-air inlet as far
as possible from swimming pool and swimming pool pump
house.
Excessive exposure to contaminated combustion air will
result in safety and performance related problems.
Solvent cements are combustible. Keep away from heat,
sparks, and open flame. Use only in well-ventilated areas.
Avoid breathing in vapor or allowing contact with skin or
eyes. Failure to follow this warning could result in fire,
property damage, personal injury, or death.
All combustion-air and vent pipes must be airtight and
watertight. Pipes must also terminate exactly as shown in Fig.
30, 31, 32, 33, or 34. Failure to follow this warning could
result in property damage, personal injury, or death.
NOTE: The minimum combustion-air and vent pipe length (each)
for these furnaces is 5 ft. Short pipe lengths (5-8 ft) may discharge
water droplets. These droplets may be undesirable, and a 12-in.
minimum offset pipe section is recommended, as shown in Fig. 28,
22
CLEARANCE (FT)
U.S.A. Canada
1 1†
3 3
3 3
1 6
1 1
4* 6‡
Note 3 Note 3