APPLIANCE APPLICATION REQUIREMENTS
Appliance operation has a significant impact on the performance of the venting system. If the appliances are sized, installed, adjusted, and operated properly, the venting system and/or the appliances should not suffer from condensation and corrosion. The venting system and all appliances shall be installed in accordance with applicable listings, standards, and codes.
The furnace should be sized to provide 100 percent of the design heating load requirement plus any margin that occurs because of furnace model size capacity increments. Heating load estimates can be made using approved methods available from Air Conditioning Contractors of America (Manual J); American Society of Heating, Refrigerating, and Air-Conditioning Engineers; or other approved engineering methods. Excessive oversizing of the furnace could cause the furnace and/or vent to fail prematurely.
When a metal vent or metal liner is used, the vent must be in good condition and be installed in accordance with the vent manufacturer’s instructions.
To prevent condensation in the furnace and vent system, the following precautions must be observed:
1.The return-air temperature must be at least 60_F (16_C) db except for brief periods of time during warm-up from setback at no lower than 55_F (13_C) db or during initial start-up from a standby condition.
2.Adjust the gas input rate per the installation instructions. Low gas input rate causes low vent gas temperatures, caus- ing condensation and corrosion in the furnace and/or vent- ing system. Derating is permitted only for altitudes above 2000 ft. (610 M).
3.Adjust the air temperature rise to the midpoint of the rise range or slightly above. Low air temperature rise can cause low vent gas temperature and potential for condensation problems.
4.Set thermostat heat anticipator or cycle rate to reduce short cycling.
Air for combustion must not be contaminated by halogen compounds which include chlorides, fluorides, bromides, and iodides. These compounds are found in many common home products such as detergent, paint, glue, aerosol spray, bleach, cleaning solvent, salt, and air freshener, and can cause corrosion of furnaces and vents. Avoid using such products in the combustion-air supply. Furnace use during construction of the building could cause the furnace to be exposed to halogen compounds, causing premature failure of the furnace or venting system due to corrosion.
Vent dampers on any appliance connected to the common vent can cause condensation and corrosion in the venting system. Do not use vent dampers on appliances common vented with this furnace.
ADDITIONAL VENTING REQUIREMENTS
A 4-in. (102 mm) round vent elbow is supplied with the furnace.
A5-in. (127 mm) or 6-in. (152 mm) vent connector may be required for some model furnaces. A field-supplied 4-in. (102 mm) to 5-in. (127 mm) or 4-in. (102 mm) to 6-in. (152 mm) sheet metal increaser fitting is required when 5-in. (127 mm) or 6-in. (152 mm) vent connector is used. See Fig. 28 - 40 Venting Orientation for approved vent configurations.
NOTE: Vent connector length for connector sizing starts at furnace vent elbow. The 4-in. (102 mm) vent elbow is shipped for upflow configuration and may be rotated for other positions. Remove the 3 screws that secure vent elbow to furnace, rotate furnace vent elbow to position desired, reinstall screws. The factory-supplied vent elbow does NOT count as part of the number of vent connector elbows.
The vent connector can exit the cabinet of the furnace through one of 5 locations.
1.Attach the single wall vent connector to the furnace vent elbow, and fasten the vent connector to the vent elbow with at least two field-supplied, corrosion-resistant, sheet metal screws located 180_ apart.
NOTE: An accessory flue extension is available to extend from the furnace elbow to outside the furnace casing. See Table 17 for accessory list. If flue extension is used, fasten the flue extension to the vent elbow with at least two field-supplied, corrosion-resistant, sheet metal screws located 180_ apart. Fasten the vent connector to the flue extension with at least two field-supplied, corrosion resistant sheet metal screws located 180_ apart.
2.Vent the furnace with the appropriate connector as shown in Fig. 28 - 40.
!CAUTION
CUT HAZARD
Failure to follow this caution may result in personal injury. Sheet metal parts may have sharp edges or burrs.
Use care and wear appropriate protective clothing, safety glasses and gloves when handling parts and servicing furnaces.
3.Determine the correct location of the knockout to be re- moved.
4.Use a hammer and screwdriver to strike a sharp blow between the tie points and work the slug back and forth until the slug breaks free.
!CAUTION
BURN HAZARD
Failure to follow this caution may cause personal injury.
Hot vent pipe is within reach of small children when installed in downflow position.
See the following instruction.
An accessory Vent Guard Kit is REQUIRED for downflow applications for use where the vent exits through the lower portion of the furnace casing. Refer to the Vent Guard Kit Instructions for complete details. See Table 17 for accessory list.
The horizontal portion of the venting system shall slope upwards not less than 1/4-in. (6 mm) per linear ft. (21 mm/m) from the furnace to the vent and shall be rigidly supported every 5 ft. (1.5
M)or less with metal hangers or straps to ensure there is no movement after installation.
SIDEWALL VENTING
This furnace is not approved for direct sidewall horizontal venting.
Per section 12.4.3 of the NFPA 54 / ANSI Z223.1-2009, any listed mechanical venter may be used, when approved by the authority having jurisdiction.
