This article lists significant air conditioning system defects, definitions, and home inspection education topics.
This article series, beginning at BUILDING DEFECTS LISTS, provides lists of common building defects and basic defect knowledge that also outline recommended curriculum content for home inspector education.
The building defects and inspection points listed in these articles also guide homeowners and home buyers to building areas that merit careful attention and often point areas of safety concern or important maintenance and repair tasks.
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5.1.1 Knowledge Base
1. Describe the function of central air conditioning systems.
2. Describe the principle of central air conditioning including refrigerant cycle and heat transfer mechanisms. Describe an operating cycle, explaining the change in temperature, pressure and state of the refrigerant.
3. List the materials and components of a central air conditioning system including the compressor, condenser coil, evaporator coil, condensate system, refrigerant lines, condenser fan, evaporator fan, duct system, thermostat.
4. Describe the operation of an evaporative cooler comparing it to refrigerant based air conditioning systems. Describe an operating cycle.
5. Describe the materials and components of a typical evaporative cooler including air handler, water reservoir, overflow, water makeup valve and float, pump, rotary drum, spray system, drip tube, air filter, cabinet, evaporative pad.
6. Describe the features of adequate installation and repair technique for refrigerant based air conditioning and evaporative coolers.
7. Define the following terms with respect to air conditioning systems:
8. Outline the typical life expectancies of the air conditioning systems described above.
9. Identify the codes or standards which apply to the air conditioning systems described above.
1. Describe the inspection procedure for refrigerant based air conditioning and evaporative coolers.
2. Identify the common defects listed on the next page.
3. Describe the implication of each defect.
4. Identify safety issues for the home inspector and occupant of the home (electric shock, injury due to moving parts).
5. Communicate findings to client verbally and in writing, recommending corrective action where needed.
CAPACITY REFRIGERANT LINES
• Oversized • Damaged
• Undersized • Leak
• Lines too warm or too cold
COMPRESSORS • Lines touching each other
• Low points or improper slope in lines
• Electric wires too small • Missing insulation
• Excess electric current draw
• Excess noise or vibration EXPANSION DEVICES - TE Valves
• Inadequate cooling
• Inoperative • Capillary tube crimped,
disconnected, leaking
• Missing electrical shutoff • Thermostatic expansion valve loose, clogged, sticking
• Out of level
• Running continuously CONDENSER FANS
• Short cycling
• Wrong fuse or breaker size • Corrosion
• Dirty
AIR COOLED CONDENSER COILS • Excess noise or vibration
• Inoperative
• Clothes dryer or water heater • Mechanical damage
exhaust too close
• Corrosion • Obstructed airflow
• Damaged
• Dirty EVAPORATOR FANS
WATER COOLED CONDENSER COILS • Corrosion
• Damage
• Cooled by pool water • Dirty
• Leak • Dirty or missing filter
• No water • Excess noise or vibration
• No backflow preventer • Inoperative
• Misadjustment of belt or pulleys
EVAPORATOR COILS • Undersized
• Corrosion DUCT SYSTEMS
• Damage
• Dirty • Dirty
• Frost • Disconnected or leaking
• No access to coil • Humidifier damper missing
• Temperature split too low • Incomplete
• Temperature split too high • Obstructed or collapsed
• Top of coil dry • Poor support
• Poor balancing
CONDENSATE SYSTEMS • Supply or return registers– obstructed
• Dirt in pan • Supply or return registers – poor location
• Inappropriate pan slope • Supply or return registers – too few
• No float switch • Undersized
• No auxiliary pan • Weak airflow
• Pan not well secured
• Pan cracked DUCT INSULATION
• Pan leaking or overflowing
• Rust or holes in pan • Incomplete
• Missing
DUCT VAPOR BARRIERS CONDENSATE PUMPS
• Damaged • Inoperative
• Missing • Leaking
• Poor wiring
CONDENSATE DRAIN LINES
THERMOSTATS
• Blocked or crimped
• Disconnected, missing • Damaged
• Improper discharge point • Dirty
• Leaking, damaged, split • Inoperative
• No trap • Loose
• Not level
• Poor adjustment or calibration
• Poor location
• Cabinet or ducts not weathertight
• Cabinet too close to grade
• Clogged pads
• Duct problems
• Electrical problems
• Excess noise or vibration
• Leaking
• Louvers obstructed
• Missing or dirty air filter
• No water
• No air gap on water supply
• Poor support for pump and water system
• Pump or fan inoperative
• Rust, mold and mildew
• Excess noise or vibration
• Inadequate attic venting
• Inoperative
Watch out: these inspection lists do not list all possible defects for the systems discussed, and not all home or building inspectors will examine all of the items listed here.
These curriculae and building defect lists are based on smilar curriculum documents first prepared by Joe Scaduto, an ASHI member who prepared course material for Northeastern University's Building Inspection Certificate program in 1988, subsequently by DF, InspectApedia's editor, for New York University ca 1988 and later, with others, recommended to ASHI, the American Society of Home Inspectors.
ASHI did not adopt this material though currently that association as well as others offer extensive HOME INSPECTOR EDUCATION material.
The curriculum and lists of defects are informed by additional analysis of the process of home inspection that was developed beginning Calgary, AB for Canadian and U.S. home inspector education and certification examinations in 1997. Other early contributors to home inspection education in the U.S. and Canada include Dr. Jess Aronstein, Alan Carson, Mike Casey, Mark Cramer, John Cox, Dwight Barnett, Douglas Hansen, Rick Heyl, Larry Hoytt, Bill Merrill, Kevin O'Malley, Dennis Robitalille, Keith Peddie, Pat Porzio, Roger Robinson.
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Continue reading at AIR CONDITIONING & HEAT PUMP SYSTEMS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.
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DEFECTS LIST - AIR CONDITIONING at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.
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