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AIR CONDITIONING & HEAT PUMP SYSTEMS
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AGE of AIR CONDITIONERS & HEAT PUMPS
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BLOWER FAN OPERATION & TESTING
BOOKSTORE - Air Conditioning "How To" Books
CAPACITORS for HARD STARTING MOTORS
CIRCUIT BREAKER SIZE for A/C or HEAT PUMP
CLEANING & Legionella BACTERIA
COMPRESSOR / CONDENSER REPAIR
CONDENSATE HANDLING, A/C
CONTROLS & SWITCHES, A/C - HEAT PUMP
COOL OFF HEAT Thermostat Switch
COOLING CAPACITY, RATED
COOLING COIL or EVAPORATOR COIL
DATA TAGS on AIR CONDITIONERS
DEFINITION of HEATING & COOLING TERMS
DIAGNOSTIC GUIDES A/C / HEAT PUMP
DUCT SYSTEM & DUCT DEFECTS
DUST, HVAC CONTAMINATION STUDY
EDUCATION, HVAC SCHOOLS
ELECTRIC MOTOR DIAGNOSTIC GUIDE
EVAPORATOR COIL or COOLING COIL
EVAPORATIVE COOLING SYSTEMS
EXPANSION VALVES, REFRIGERANT
FAN, AIR HANDLER BLOWER UNIT
FAN AUTO ON THERMOSTAT SWITCH
FAN, COMPRESSOR/CONDENSER UNIT
FAN CONVECTOR HEATERS - HYDRONIC COILS
FAN NOISES, HVAC
GAS DETECTION INSTRUMENTS
GAS LAWS & CONSTANTS
GAUGE, REFRIGERATION PRESSURE TEST
HEAT LOSS (or GAIN) IN BUILDINGS
HEAT LOSS (or GAIN) INDICATORS
HEAT LOSS R U & K VALUE CALCULATION
HUMIDITY LEVEL TARGET
INSPECTION CHECKLIST - OUTDOOR UNIT
INSPECTION LIMITATIONS, A/C SYSTEMS
LOST COOLING CAPACITY
LOW VOLTAGE TRANSFORMER TEST
MANUALS & PARTS GUIDES - HVAC
MOTOR OVERLOAD RESET SWITCH
MOLD in AIR HANDLERS & DUCT WORK
NOISE AIR CONDITIONER / HEAT PUMP
ODORS in AIR HANDLERS & DUCT WORK
OPERATING COST, AIR CONDITIONER
OPERATING DEFECTS, AIR CONDITIONING
OPERATING TEMPERATURES, AIR CONDITIONER
PORTABLE ROOM AIR CONDITIONERS
PRESSURE READINGS, REFRIGERANT
REPAIR GUIDES A/C / HEAT PUMP
REPAIR & DIAGNOSTIC FAQs for A/C
REFRIGERANTS & PIPING
RETROFIT SIZING for A/C or HEAT PUMPS
SEER RATINGS & OTHER DEFINITIONS
SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS
THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES
WATER COOLED AIR CONDITIONERS
WINDOW / WALL AIR CONDITIONERS
WINDOW / WALL A/C SUPPORTS
Contamination in air conditioning or heating ducts:
List of HVAC air duct contamination sources & types, diagnostic articles & duct contaminant or odor detection, testing & contaminant removal or prevention advice.
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This article series addresses just about every common source of contaminants in heating & cooling duct systems, such as sources of bacteria, dust, fiberglass, mold or odors that appear to originate in or be transported by the buildings air duct system.
[Click to enlarge any image]
Below is an alphabetical list of common air duct contaminants and contamination sources or duct test & inspection methods.
Following our list of duct contaminant diagnostic articles we illustrate and discuss some common examples of air duct contamination, dust, dirt and debris - or perhaps of more concern, pathogens.
Watch out: don't panic if you see dust inside the HVAC system, or exposed fiberglass. Both of these conditions are common and do not necessarily mean that the air ducts are unsanitary or unsafe.
However if you see signs of water, visible mold, flooding, rodents, or if you see that the duct interior has been damaged like the fiberglass-lined duct shown a the top of this page (DUCT DAMAGE, MECHANICAL) there may indeed be a problem that needs to be addressed.
Article Series Contents
At above left we show transite HVAC ducts routed in a floor slab immediately over a sewer line. When the sewer line leaked sewage odors were picked up in and transported by the in-slab ductwork.
At above right we illustrate an air duct that was routed below the first floor of a buildnng and accessible from the basement.
A look inside showed us that there had been of a history of flooding - dirt and mud on the duct bottom - meaning that floodwaters had at one time filled the basement.
Watch out: area flooding may contaminate ductwork with sewage or other pathogens even for above-ground-level HVAC ducts, while a building sewage backup can certainly contaminate ductwork run in floors or in a floor slab.
At above left we illustrate an abandoned HVAC duct in a concrete floor slab. It's quite apparent that the area remains wet along with an added risk of contaminants of sewage, pesticides, rodents, insects, or anything that spilled on the floor in this area.
Our HVAC duct interior photograph at above right shows a melange of contamination by animal hair, dog food, and rodent droppings. Mice were eating the dog food that spilled into this return air duct opening at a floor register. The potential pathogens invovled here include at least bacteria, possibly hantavirus and mold.
Continue reading at AIR LEAKS in RETURN DUCTS or select a topic from the More Reading links shown below.
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