Allied Air Enterprises 80G1UH, A80UH Unconfined Space, Confined Space, Figure Air from Inside

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Unconfined Space

All gas fired appliances require air for the combustion process. If sufficient combustion air is not available, the furnace or other appliances will operate inefficiently and unsafely. Enough air must be provided to meet the needs of all fuel burning appliances and appliances such as exhaust fans which force air out of the house. When fireplaces, exhaust fans, or clothes dryers are used at the same time as the furnace, much more air is necessary to ensure proper combustion and to prevent a downdraft. Insufficient air causes incomplete combustion which can result in carbon monoxide.

In addition to providing combustion air, fresh outdoor air dilutes contaminants in the indoor air. These contaminants may include bleaches, adhesives, detergents, solvents and other contaminants which can corrode furnace components.

The requirements for providing air for combustion and ventilation depend largely on whether the furnace is installed in an unconfined or a confined space.

Unconfined Space

An unconfined space is an area such as a basement or large equipment room with a volume greater than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space. This space also includes adjacent rooms which are not separated by a door. Though an area may appear to be unconfined, it might be necessary to bring in outdoor air for combustion if the structure does not provide enough air by infiltration. If the furnace is located in a building of tight construction with weather stripping and caulking around the windows and doors, follow the procedures in the air from outside section.

Confined Space

A confined space is an area with a volume less than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space. This definition includes furnace closets or small equipment rooms.

When the furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air must be handled by ducts which are sealed to the furnace casing and which terminate outside the space containing the furnace. This is especially important when the furnace is mounted on a platform in a confined space such as a closet or small equipment room. Even a small leak around the base of the unit at the platform or at the return air duct connection can cause a potentially dangerous negative pressure condition. Air for combustion and ventilation can be brought into the confined space either from inside the building or from outside.

Equipment in Confined Space - All Air From Inside

NOTE: Each opening shall have a free area of at least one square inch per 1,000 Btu (645 mm² per .29 kW) per hour of the total input rating of all equipment in the enclosure, but not less than 100 square inches (64546 mm²).

Figure 3

Air from Inside

If the confined space that houses the furnace adjoins a space categorized as unconfined, air can be brought in by providing two permanent openings between the two spaces. Each opening must have a minimum free area of 1 square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of total input rating of all gas fired equipment in the confined space. Each opening must be at least 100 square inches (64516 mm2). One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches (305 mm) of the bottom. See Figure 3.

Air from Outside

If air from outside is brought in for combustion and ventilation, the confined space must have two permanent openings. One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches (305 mm) of the bottom. These openings must communicate directly or by ducts with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of 1 square inch (645 mm2) per 4,000 Btu (1.17 kW) per hour of total input rating of all equipment in the en-closure. See Figures 4 and 5. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch (645 mm2) per 2,000 Btu (.56 kW) per total input rating of all equipment in the enclosure. See Figure 6.

506526-01

Issue 1031

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Contents Warm Air Gas Furnace TABLE OF CONTENTSINSTALLATION INSTRUCTIONS A80UH & 80G1UHFRONT VIEW A80UH & 80G1UH Unit Dimensions - inches mmSIDE VIEW 506526-01 A80UH & 80G1UHA80UH & 80G1UH Gas Furnace Safety InformationInstalled Locations DANGERUse of Furnace as a Construction Heater Installed in Combination with a Cooling CoilHeating Unit Installed Upstream of Cooling Unit Temperature Rise215 Metropolitan Drive West Columbia, SC GeneralProduct Contains Fiberglass Wool Allied Air Enterprises, IncFigure Air from Inside Unconfined SpaceConfined Space Equipment in Confined Space - All Air From InsideEQUIPMENT IN CONFINED SPACE Upflow Application Installation Clearances Setting EquipmentUpflow Applications 5.Bottom and one side return air Return Air - Upflow Applications1800 cfm 850 L/s must have one of the following 3.Bottom return air 4.Return air from both sidesHorizontal Applications Horizontal Application Installatioin clearancesRemoving the Bottom Panel Removing the Bottom Panel FigureSupply Air Plenum Horizontal Application Unit installed on PlatformFilters Table Duct SystemFigure UPFLOW POSITION VentingMounting Screws Location Figure UPFLOW POSITION UPFLOW POSITIONHORIZONTAL RIGHT POSITION Horizontal PositionHORIZONTAL LEFT POSITION Figure HORIZONTAL LEFT POSITIONIssue Venting Using a Masonry ChimneyCommon Venting Using Metal Lined Masonry Chimney Vent Connection FigureGeneral Venting Requirements Page 17 of Issue506526-01 Serving a Single Category I ApplianceIssue Page 18 of506526-01 Serving a Single Category I ApplianceIssue Page 19 ofServing Two or More Category I Appliances Vent Connector CapacityServing Two or More Category I Appliances Common Vent CapacityServing Two or More Category I Appliances Table Common Vent CapacityServing Two or more Category I Appliances Table Vent Connector CapacityPage 22 of Removal of the Furnace from Common VentCARBON MONOXIDE POISONING HAZARD IssueIssue Gas PipingGas Supply Gas Pipe Capacity - ft³/hr m³/hrPage 24 of Possible Gas Piping ConfigurationsFigure Horizontal Applications IssueINTERIOR MAKE-UPBOX INSTALLATION Figure INTERIOR MAKE-UPBOX INSTALLATION FigureLeak Check Figure Electrical ELECTROSTATIC DISCHARGE ESDCondensing Unit Thermostat Designations Accessory TerminalsGenerator Use - Voltage Requirements Thermostat506526-01 Wiring Diagram FigureIssue Page 27 ofIntegrated Control Typical Field Wiring Diagram FigureAutomatic Hot Surface Ignition System Gas Valve Operation Figure FOR YOUR SAFETY READ BEFORE LIGHTING UNITUnit Start-UP Placing the Furnace into OperationManifold Pressure Measurement Gas Pressure Adjustment Gas Flow ApproximateHeating Sequence Of Operation Figure Supply Pressure MeasurementPressure Switch Manifold Pressure Settings and Pressure SwitchOther Unit Adjustments Flame Rollout SwitchesElectronic Ignition Thermostat Heat AnticipationElectrical Blower SpeedsFlue And Chimney ServiceELECTRICAL SHOCK, FIRE OR EXPLOSION HAZARD Blower506526-01 Cleaning the Heat Exchanger and BurnersIssue Page 34 ofNOx INSERTS Figure Remove 5 Screws If NecessaryPage 36 of PLANNED SERVICEFAILURE CODES IssueControl Panel REPAIR PARTS LISTCabinet Parts Heating Parts506526-01 START-UP& PERFORMANCE CHECK LIST UNIT SET UPIssue Page 38 of506526-01 IssueUNIT OPERATION Page 39 of