IDENTIFYING MECHANICAL SYSTEMS IMPROVING DUCT SYSTEMS WEATHERIZATION INSTALLERTECHNICIAN

IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS WEATHERIZATION INSTALLER/TECHNICIAN FUNDAMENTALS Identifying Mechanical Systems and Improving Duct Systems WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 1 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Learning Objectives IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS By attending this session, participants will be able to: • Identify common mechanical systems, including combustion appliances and cooling systems. • Discuss clearance to combustibles requirements for various vent pipe types. • Identify various electrical, plumbing, and safety components of mechanical systems. • Illustrate proper combustion vent system exhaust system installation. 2 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Learning Objectives IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS By attending this session, participants will be able to: • Explain how a home’s forced air distribution system works. • Describe mobile home duct configurations. • Identify and diagnose duct leakage problems. • Fix leaky ducts using correct materials and techniques. • Make other duct system improvements. 3 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Combustion, Distribution & Venting IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Vent Supply Air Combustion Gases Return Air Dilution Air Heat Exchanger Gas Valve Main Burner Combustion Air Graphic developed for the US DOE WAP Standardized Curricula 4 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Clearance to Combustibles IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Oil and Wood Single wall 18” Double Wall Super Six, Dura Vent 6” Manufactured Chimney 2” or per Manufacturer Instructions Gas Single Wall 6” Double Wall B-Vent or B-W Vent 1” 5 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 Photo Courtesy of NRCERT eere. energy. gov

Unvented Space Heaters IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos Courtesy of NRCERT Unvented space heaters release all of their combustion byproducts into the home. In addition to carbon dioxide and water vapor, compounds of carbon monoxide, excess air, and sulfur dioxide will be present. 6 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Furnaces IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Furnaces heat air Single wall flue for oil heat Open ended duct Photo courtesy of PA Weatherization Training Center 7 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Furnace Test Locations #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Atmospheric Furnace 80+ Induced Draft Furnace CO & Draft CO Figures courtesy of Corporation for Ohio Appalachian Development (COAD) 8 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Furnace Test Locations #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS 90+ Condensing Furnace Floor Furnace CO & Draft CO Draft Figures courtesy of COAD 9 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Furnace Test Locations #3 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Fuel Oil Furnace CO Barometric Damper Draft Photo courtesy of NRCERT Figure courtesy of COAD 10 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Oil Burner Components #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Fuel filter Overheat shutoff fuel valve Cutaway blast tube Burner air adjustment Retention head Source: R. Karg Non-retention head burner Retention head burner • Typically 1, 725 RPM • Should be replaced • Typically 3, 450 RPM • 10% more efficient 11 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Oil Burner Components #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Source: Heating with Oil, Natural Resources Canada, 1998. 12 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Oil Burner Components #3 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Electrodes for burner ignition Burner fan Inside the burner blast tube Oil line to nozzle Source: R. Karg Open transformer Cad cell Source: R. Karg 13 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 Electrode springs (thousands of volts) eere. energy. gov

Oil-Fired Boiler IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Boilers heat water Source: Natural Resources Canada, www. nrcan. gc. ca 14 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Natural Draft Boiler and Water Heater IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Source: R. Karg 15 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Forced Draft Boiler IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Forced Draft Unit This boiler has a high static pressure burner. It vents through the wall and its combustion supply air is vented directly to the burner from the outdoors. The burner has a special cover that allows the outdoor air to flow directly to the burner. Photo courtesy of R. Karg 16 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimney and Vent Connectors IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Combustion gases mixed with room air Draft diverter Chimney Vent Dilution air Draft hood Water heater Gas heating appliance Graphic developed for the US DOE WAP Standardized Curricula 17 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Forced Air System Operation #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS A typical mobile home downflow distribution system Graphic developed for the US DOE WAP Standardized Curricula 18 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Forced Air System Operation #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Return Air Furnace Vents Duct Graphic developed for the US DOE WAP Standardized Curricula 19 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Duct Components IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Furnace plenum Main duct run Photo courtesy of PA WTC Fabricated Ducts 20 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Duct Location IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Lengthwise Floor Joist System Crosswise Floor Joist System Images courtesy of PA WTC 21 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Problems and Opportunities IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS New factory installation includes duct tape Failed duct tape Photos courtesy of PA WTC 22 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Visual Checks #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Duct registers are common leakage sites. Photos courtesy of PA WTC 23 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Visual Checks #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos courtesy of PA WTC Desperate times call for desperate measures… …when the crawl space is the warmest room of the house! 24 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Visual Checks #3 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Branch duct leakage Large holes Photos courtesy of PA WTC 25 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Visual Checks #4 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Bottom of the heat exchanger Smashed boot Main duct Photo courtesy of PA WTC No heat? No wonder! 26 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Visual Checks #5 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos courtesy of the US Department of Energy The flashlight and mirror trick Is that a squeegee down there? 27 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Visual Checks #6 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Typical Air Leakage Locations Register Boot Furnace Connection Branch Duct Termination CT U D NK TRU Crossover Duct Graphic developed for the US DOE WAP Standardized Curricula 28 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Pressure Pan Testing IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Remember this number • Depressurize the home to 50 pascals. • Pressure pan each register location. • Record pressure differences. • Repair ducts and retest. The goal is to reduce pressure pan readings at each register location to less than 1 pascal. Photo Source: US Department of Energy 29 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing & Sealing Ducts #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Duct repair and sealing techniques • Inspect ducts and boots. • Repair or replace ducts and boots. • Clean ducts. • Seal with mastic and fiberglass mesh tape. • Seal ends of trunk line. • Repair and seal furnace base. Photo courtesy of the US Department of Energy Duct inspection and modification tools 30 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing & Sealing Ducts #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos courtesy of the US Department of Energy Inspect for blockage and loose seams. Check the flanges and inspect for damage. 31 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing & Sealing Ducts #3 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Make sure to clean ducts before sealing. Photo courtesy of the US Department of Energy 32 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing & Sealing Ducts #4 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Repair or replace the boot. Photo courtesy of the US Department of Energy 33 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing & Sealing Ducts – Materials #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photo courtesy of the US Department of Energy Photo courtesy of PA WTC Aluminum coil stock and boot fabrication 34 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing & Sealing Ducts – Materials #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Butyl-backed tape Photo courtesy of PA WTC Image Source: http: //www. hardcast. com/PRODUCTS/pr_detail. asp? pid=3 35 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing & Sealing Ducts – Materials #3 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Mastic sealant Photo courtesy of the US Department of Energy Image Source: http: //www. rcdmastics. com/pd 6. asp 36 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Sealing with Mastic #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos courtesy of the US Department of Energy Use fiberglass mesh tape to span gaps larger than ¼ inch. Latex gloves are often your mastic brush. 37 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Sealing with Mastic #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos courtesy of the US Department of Energy Seal the end of the trunk line by stuffing backer material into the duct past the last register and seal with mastic. Use screws to hold carpet up until mastic dries. 38 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing and Sealing Ducts #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photo courtesy of WV GOEO Seal the duct, then patch the belly board. Photo courtesy of PA WTC Mechanically fasten and seal with butyl-backed aluminum tape or mastic. 39 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing and Sealing Ducts #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photo courtesy of PA WTC Re-attach disconnected ductwork 40 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Repairing and Sealing Ducts - Review IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Concentrate on the following locations: – Risers – Ends – Branch ducts – Furnace plenum • You may need to cut the rodent barrier to access some leaks. • Never use duct tape. • Mechanically fasten components where necessary. 41 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Post Pressure Pan Testing IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos courtesy of the US Department of Energy Results! 42 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Pressure Balancing the System IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Measure room pressure imbalances • Room pressure imbalances over 4 pascals should be remedied by adding supply or return air, then retesting. • Make sure that doors to interior rooms are sufficiently undercut to allow air to return to the furnace. Photo courtesy of PA WTC 43 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Other Duct System Improvements IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS • Replace damaged registers • Remove obstructions • Balance the system Photos courtesy of PA WTC 44 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Venting Systems IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Venting Systems should: • Carry all combustion byproducts to outdoors. • Establish draft quickly. • Be properly sized with minimal restrictions. • Have long durability (corrosion resistance). • Protect surrounding materials from overheating. • Have adequate make up air. 45 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimneys and Vents IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS From hot water tank Single wall vent Chimney From furnace Photo courtesy of PA Weatherization Training Center 46 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Vent Types IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS • Masonry chimneys • Type B-vents – double wall, round Masonry Chimney and B-Vent • Type BW-vents – double wall, oval • Type L-vents – more heat, corrosion resistant • Single wall metal – interior only • Plastic pipe vents – low temperature condensing furnaces 47 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 Photo courtesy of NRCERT eere. energy. gov

Factors That Affect Vent Operation IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS • Vent gas temperature • Heat loss from the vent • Height of the venting system • Capacity of the venting system • Restrictions in the venting system • Ambient temperature • Negative pressure in the combustion appliance zone (CAZ) See a problem here? Photo courtesy of NRCERT 48 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimney Specifications IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Masonry chimney is too short Photo Courtesy of PA Weatherization Training Center 49 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimneys and Vents #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Check for: • Connections, obstructions • Holes • Sound liner • Slope of horizontal runs • Extend 3’ above roof penetration • Appropriate type and size for the appliance • Proper diameter 50 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimneys and Vents #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Blocked chimney Missing cleanout Photos Courtesy of PA Weatherization Training Center Chimneys and vents must not be blocked and must have no holes in the chimney or vent. 51 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimneys and Vents #3 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Improper slope Hole in vent connector Photos Courtesy of PA Weatherization Training Center Improper Slope Hole in Vent Connector 52 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimneys and Vents #4 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Reduced vent connector No vent connector Photos Courtesy of PA Weatherization Training Center Reduced vent connector out of compliance with code No vent connector 53 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Water Heaters IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photo courtesy of PA Weatherization Training Center Burn marks above the burner compartment are evidence of flame roll out. Photo courtesy of NRCERT Spillage of flue gases or insufficient draft is often a result of an improper installation such as this. 54 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Testing Water Heaters #1 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Test for CO on both sides of the baffle. Photo courtesy of NRCERT Figure courtesy of COAD Test for draft above the draft diverter. Atmospheric Hot Water Tank 55 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Testing Water Heaters #2 IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Draft diverter Photos courtesy of NRCERT Test for CO directly into the breech of the unit on both sides of the baffle that runs up through the center of the tank. On start up, time the amount of spillage. Then test draft above the draft diverter. Spillage should not exceed one minute. 56 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Chimney Liner IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Photos courtesy of NRCERT 57 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Air Conditioning Systems IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Air Conditioning Units Packaged • Heat Pump Split System • Condenser outdoors • A/C coil indoors, often in furnace, heat pump, or • Often mounted on roof supply duct CONDENSER or concrete slab outdoors AIR HANDLER • Central System • Includes Room A/C units (most common in low-income homes) * All A/C need clean filters and coils to allow good air flow and efficient heat transfer. Mini-split ductless systems place the condenser outdoors, air handler indoors. 58 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Indoor and Outdoor Coils IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Outdoor coils • Cleaning frequency depends on levels of dust and pollen in area • High levels: Clean annually • Low levels: Every 3 years Indoor • Should be protected by well-fitting clean filter • Keeps blower and coils clean Indoor coils • Easier to replace or clean filters than blowers or coils Adapted from image on www. home. howstuffworks. com 59 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Parts of Room A/C IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS g n i s u ho r o o d t il o c indoor coil ou e filt compressor condensate drain r s ol r t n co le b va o rem ill r g Photo courtesy of Energy Out West Weatherization Field Guide. Copyright Saturn 2009 www. srmi. biz 60 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Central A/C Components IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS The outdoor condenser and coils dissipate collected heat to the outdoor air. In dusty climates, the coils should be cleaned annually to maintain efficient performance. Adapted from image on www. home. howstuffworks. com 61 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS Covering the unit during periods of disuse prevents clogging with leaves and other debris. Photo courtesy of The U. S. Department of Energy 62 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov

Summary IDENTIFYING MECHANICAL SYSTEMS & IMPROVING DUCT SYSTEMS • Furnaces heat air and use ducted distribution systems. • Boilers heat water and transport heat through the living space through pipes connected to radiators. • Cooling systems can be packaged or split systems. If the condenser and coils are in separate locations, it is a split system. • Most ducts are very prone to leakage. • Diagnosing and repairing duct leakage is the single, most costeffective measure you can apply to many mobile homes. • Effective duct sealing is possible through the use of innovative duct sealing materials. • Other duct improvement measures, such as cleaning, removing obstructions, and system balancing can improve comfort and lower fuel bills. 63 | WEATHERIZATION ASSISTANCE PROGRAM STANDARDIZED CURRICULUM – July 2012 eere. energy. gov