| COMBUSTION AIR |
3/8" ID TUBE | INTAKE HOUSING |
BURNER | |
| BOX |
!CAUTION
3/16"
DRILL
TRAP
TO OPEN
DRAIN
COMBUSTION
AIR PIPE
4″
(102mm)
MIN
UNIT CORROSION HAZARD
Failure to follow this caution may result in reduced furnace component life.
Air for combustion must not be contaminated by halogen compounds, which include fluoride, chloride, bromide, and iodide. These elements may corrode heat exchangers and shorten furnace life. Air contaminants are found in aerosol sprays, detergents, bleaches, cleaning solvents, salts, air fresheners, and other household products.
A93035
Fig. 40 - Intake Housing Plug Fitting Drain
8.Install casing hole filler cap
Attachment of Combustion Air Intake Housing Plug Fitting
The
NOTE: DO NOT
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
NOTE: (Direct Vent /
Combustion Air Termination - Ventilated Combustion Air Option
Provisions for adequate combustion, ventilation, and dilution air must be provided in accordance with:
SU.S. Installations: Section 9.3 NFPA 54/ANSI
SCanadian Installations: Part 8 of
Combustion air is piped directly to the burner box on furnace using the same materials used to vent the furnace. (See Table 5.) The combustion air pipe is terminated in an attic or crawl space that is well ventilated with OUTDOOR AIR and is well isolated from the living space or garage. If the furnace is installed in a well ventilated attic, crawlspace or other enclosure, the combustion air pipe can be terminated in the same space.
The combustion air pipe cannot be terminated in attics or crawlspaces that use ventilation fans designed to operate during the heating season. If ventilation fans are present in these areas, the combustion air pipe must terminate outdoors as a Direct Vent/
!WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
The operation of exhaust fans, kitchen ventilation fans, clothes dryers, attic exhaust fans or fireplaces could create a NEGATIVE PRESSURE CONDITION at the furnace. Makeup air MUST be provided for the ventilation devices, in addition to that required by the furnace. Refer to the Carbon Monoxide Poisoning Hazard warning at the end of this section to determine if an adequate amount of
NOTE: Combustion air pipe must have the same diameter as vent pipe.
An attic or crawlspace may be considered a space that freely communicates with the outdoors provided there are adequate permanent ventilation openings directly to outdoors having free area of at least
NOTE: In determining the free area of an opening, the blocking effect of the louvers, grilles, and screens must be considered. If the free area of a louver or grille design is unknown, it may be assumed that wood louvers have a 20 percent free area, and metal louvers or grilles have a 60 percent free area. Screens, when used, must not be smaller than
!WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
Many homes require air to be supplied from outdoors for furnace combustion, ventilation, and dilution of flue gases.
The furnace combustion air supply must be provided in accordance with this instruction manual.
Attic terminations require at least (1) 90 degree elbow, with the open end pointing horizontally or downward. The open end of the elbow must be at least
355CAV
35