RESIDENTIAL CONDENSING GAS FURNACES Vent Design & Installation Training Spring 2014 UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Vent Design & Installation Training Contents Section 1: 35” Condensing Furnace Design Section 2: National and International Codes Section 3: Vent Design Considerations Section 4: Vent Installation Section 5: Results of Poor Vent Design and Installation Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Section 1 35” Condensing Furnace Design Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Condensation Management Comparison System Condensate Load Vent Legacy 92% New 92% New 98% high Flue Gas Temp low Vapor Liquid Liquid Vapor Vapor Liquid Drain Lower flue gas temps More liquid condensate in vent UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Vent Condensate Load Comparison Legacy 92% New 92% New 98% Inducer Airflow Vapor Vapor Vapor Liquid Liquid Liquid More liquid in vent Vent pitch is important UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

(Single & 2-Stage Models) RESIDENTIAL CONDENSING GAS FURNACES Normal Pressure Switch Operation: Single & 2-Stage LPS (Low Pressure Switch) Measures: collector box pressure Purpose: Prevent furnace operation during restricted heat exchanger, trap or condensate drain Status Code 3 (Single & 2-Stage Models) HPS (High Pressure Switch) Measures: inducer housing pressure Purpose: Prevent furnace operation during restricted vent Pressure switches are used to prevent CO from backing up into a structure. Pressure switches are not for “furnace proving”. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Section 2 National and International Codes Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

PLUMBING CODES Applicability to Fuel Gas Appliance Venting National Standard Plumbing Code 2009 International Plumbing Code 2012 NSPC plumbing definition excludes piping for ‘environmental control’. IPC plumbing definitions excludes fuel gas appliance exhaust or combustion air. NSPC vent definitions do not refer to fuel gas appliance exhaust. IPC vent definitions do not include fuel gas appliance exhaust or combustion air. Fuel gas appliances are regulated by the National or International Fuel Gas Code or International Residential Code. Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

FUEL GAS CODES Vent, Combustion Air and Make-up Air NATIONAL FUEL GAS CODE 2012 ANSI Z223.1, NFPA 54 INTERNATIONAL FUEL GAS CODE 2012* *IFGC applies to residential gas furnaces in 1 or 2 family dwellings and townhouses. NFGC and IGFC refer to manufacturer’s Installation Instructions/Manual for vent design, sizing and installation. IFGC refers to manufacturer’s Installation Instructions/Manual for vent support, combustion and ventilation air requirements Vent and combustion air termination location is specified in NFGC. Make-up and combustion air is specified in IFGC. Refer to National and International Fuel Gas Codes and manufacturer’s Installation Instructions/Manual for vent, combustion air, ventilation and make-up air design and installation. The condensing furnace is a category IV appliance. Moves gases, lighter than air Uses neutral air pressure. 9 UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Section 3 Vent Design Considerations Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Nuisance HPS Trip Causes: Vent Length Cause 1: Maximum vent length in Installation Instructions were exceeded. Cause 2: Smallest practical vent diameter not used. Affect on Operation: Vent system pressure drop exceeds furnace capacity. Starves burner of combustion air resulting in incomplete combustion. Affect on Operation: Vent system pressure drop is too low. Too much combustion air resulting in unstable flame. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Nuisance HPS Trip Causes: Vent Termination Cause: Vent termination/s are below the snow line. Cause: Combustion air and vent termination/s are located too close to another fuel gas appliance vent, dryer vent and plumbing stack. Affect on Operation: Vent or combustion intake termination freezes Affect on Operation: Combustion products are pulled into combustion air intake (recirculation). Burners are starved of oxygen which results in incomplete combustion. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Nuisance HPS Trip Causes: Termination Location Cause: Vent and combustion air termination is not protected from prevailing winds. Cause: Vent and combustion air termination is located in an inside corner. Affect on Operation: Inducer is unable to overcome static wind pressure. Affect on Operation: Combustion products are pulled into combustion air intake (recirculation). Burners are starved of oxygen which results in incomplete combustion. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Section 4 Vent Installation Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Nuisance HPS Trip Causes: Vent Installation Cause: Inadequate pipe support resulting in sags. Cause: Inadequate slope Affect on Operation: Condensate is accumulates at elbows or horizontal sections and partially blocks flow. Large condensate masses will slug back to the inducer creating a pressure wave. Affect on Operation: Inducer pressure can start condensate waves in the low section of vent pipe, which varies the static pressure on the inducer. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Nuisance HPS Trip Causes: Vent Installation Horizontal sections less than 4 feet, Elbow sockets do not allow adequate slope, use 45 elbows UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

RESIDENTIAL CONDENSING GAS FURNACES Section 5 Results of Poor Vent Design and Installation Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

Heat Exchanger Corrosion RESIDENTIAL CONDENSING GAS FURNACES Results of Poor Vent Design & Installation Status Code 3, No Heat Loss of Flame Sense Heat Exchanger Corrosion Customer Dissatisfaction UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

Resources Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

Air Pressure from Inducer RESIDENTIAL CONDENSING GAS FURNACES Plumbing vs Condensing Furnace Vent Systems Plumbing Vent, Stack Pipe Draws in oxygen for waste digestion Expels harmful vapors through roof Plumbing Drain Flushes liquids & solids Condensing Furnace Vent Pulls in combustion air (negative pressure) Pushes out flue gas (positive pressure) Moves liquid condensate to furnace Gravity used to overcome inducer air pressure and condensate surface tension. Gravity Surface tension Air Pressure from Inducer Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

NATIONAL STANDARD PLUMBING CODE 2009 Definition and Scope for Plumbing Uses neutral air pressure. Moves gases, lighter than air Plumbing definition excludes piping for ‘environmental control’. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

NATIONAL STANDARD PLUMBING CODE 2009 Definition and Scope for Vent Uses neutral air pressure. Moves gases, lighter than air No vent definitions refer to fuel gas appliance exhaust. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL PLUMBING CODE 2012 Scope of Plumbing Code Uses neutral air pressure. Moves gases, lighter than air Fuel gas appliances are regulated by the International Fuel Gas Code. Fuel gas appliances in houses are regulated by the International Residential Code. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL PLUMBING CODE 2012 Definition of Plumbing Uses neutral air pressure. Moves gases, lighter than air Plumbing definitions do not include fuel gas appliance exhaust or combustion air. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL PLUMBING CODE 2012 Definition of Vent Vent definitions do not include fuel gas appliance exhaust or combustion air. Uses neutral air pressure. Moves gases, lighter than air UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

NATIONAL FUEL GAS CODE 2012 ANSI Z223.1, NFPA 54 Vent Code Uses neutral air pressure. Moves gases, lighter than air Vent and combustion air termination location is specified in NFGC. NFGC refers to manufacturer’s Installation Instructions/Manual for vent sizing and installation. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL FUEL GAS CODE 2012 Scope Uses neutral air pressure. Moves gases, lighter than air Applies to residential gas furnaces in 1 or 2 family dwellings and townhouses. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL FUEL GAS CODE 2012 Definition of Direct Vent Uses neutral air pressure. Moves gases, lighter than air The condensing furnace is a category IV appliance. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL FUEL GAS CODE 2012 Vent Code Uses neutral air pressure. Moves gases, lighter than air IFGC refers to manufacturer’s Installation Instructions/Manual for vent design, sizing and installation. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL FUEL GAS CODE 2012 Definition of Direct Vent Uses neutral air pressure. Moves gases, lighter than air IFGC refers to manufacturer’s Installation Instructions/Manual for vent installation and support requirements. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL FUEL GAS CODE 2012 Definition of Direct Vent Uses neutral air pressure. Moves gases, lighter than air IFGC refers to manufacturer’s Installation Instructions/Manual for combustion and ventilation air. Make-up and combustion air specified in IFGC. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution

INTERNATIONAL FUEL GAS CODE 2012 Definition of Direct Vent Uses neutral air pressure. Moves gases, lighter than air Vent termination location is specified in International Fuel Gas Code. UTC Building & Industrial Systems Confidential and Proprietary Information – Not For Further Distribution