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AIR CONDITIONING & HEAT PUMP SYSTEMS
A/C - HEAT PUMP CONTROLS & SWITCHES
A/C DATA TAGS
A/C DIAGNOSTIC FAQs
A/C TYPES, ENERGY SOURCES
AGE of AIR CONDITIONERS & HEAT PUMPS
AIR CONDITIONER BTU CHART
AIR CONDITIONER COMPONENT PARTS
AIR FILTERS for HVAC SYSTEMS
AIR FLOW MEASUREMENT CFM
AIR HANDLER / BLOWER UNITS
BACKUP HEAT for HEAT PUMPS
BLOWER FAN CONTINUOUS OPERATION
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 & CONDENSING COIL, A/C
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
Rooftop HVAC equipment: this article describes rooftop mounted HVAC systems - rooftop air conditioners, rooftop heat pumps, and rooftop heating equipment. We describe types of roof-mounted HVAC equipment and common inspection points, operating problems, and repair approaches. At page top is a roof mounted swamp cooler or evaporative cooling system on a private home in Tucson.
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Commercial rooftop-mounted combined air conditioning or heat pump units
Rooftop mounted central air conditioning systems may include both the cooling unit (evaporator coil, blower fan, filters) and the compressor/condenser unit in one package. At above right is a complex of roof-mounted AC/heat pump systems on a Christchurch, New Zealand high rise building roof. These units may be a bit crowded as well as blown-on by the building's ventilation system openings at the upper right of the image.
At above left is a flat-roof mounted commercial cooling system located in New York.
In many commercial installations, the entire area over a suspended ceiling may serve as one giant return plenum through which pass the supply ducts, delivering air to individual supply registers.
While the list above describes the common components of a typical residential air conditioning system, other configurations and packaged units are also in increased use in both residential and commercial installations.
Alternative HVAC designs may combine all components except for the duct work in a rooftop mounted unit such as the one shown above where it was mounted on a flat roof over offices at a commercial building.
Split-System A/C Rooftop Mounted Air Conditioners & Heat Pumps
The outdoor compressor/condenser unit of split-system air conditioners and heat pumps is also commonly mounted on rooftops, especially flat or low-slope roofs such as the unit shown at left.
Installation requirements for rooftop-mounted split system compressors / condenser units include both a service disconnect (circled in our photo) and often additional measures to assure that the unit is properly padded to avoid damage to the roof membrane, and to assure that the unit is properly levelled.
IN our OPINION, where rooftop mounted split system condenser units are exposed to high temperatures system operating efficiency and costs may be affeted.
Details are at SPLIT SYSTEM AIR CONDITIONERS & HEAT PUMPS
These photographs show what happens when a rooftop packaged-terminal air-conditioning air handler
Water ponded on the old, concave sections of air conditioning ducts on the roof of this commercial office space. As water leaked into the duct system it saturated fiberglass duct liner which in turn, had its normal coating of organic dust and debris from the building, risking an indoor mold or pathogen problem for some of the occupants.
The cure for these duct leaks was costly: it was determined that it was less costly to completely replace the rooftop ducts with new metal ducts using outside insulation than it would have been to remove the contaminated fiberglass liner, clean the existing ducts, repair the leaks, and insulate their exterior. The work was combined with other building HVAC cleaning and repairs.
Support Requirements for Rooftop-Mounted HVAC Equipment
Shown at left, support system for rooftop air conditioners / heat pumps mounted on a metal roof in Christchurch, New Zealand.
Continue reading at SPLIT SYSTEM Ductless Air Conditioners or select a topic from the More Reading links shown below.
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Frequently Asked Questions (FAQs)
(May 18, 2014) :yn said:
Is it wise and/or possible to put the compressor for a multi split unit in the attic of a home?
OPINION: I can't say if it's wise or not. It's more stunning. Normally the compressor/condenser is placed outside where it exchanges heat with outdoor air. IN an attic putting the compressor condenser unit in such a location would be very unusual and probably not work.
(July 28, 2014) DE said:
Is it possible to move a roof mounted HVAC unit from the roof to a platform adjacent to the house? The roof has been leaking where the unit has been mounted & we'd like to know if we can move the unit to prevent further damage.
Yes if you are talking about a refrigerant based system, but depending on the type of system you are moving the cost could be considerable. For example if the rooftop unit includes the blower assembly.
Rooftop swamp coolers are usually designed to work just in that location.
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