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AIR CONDITIONING & HEAT PUMP SYSTEMS
A/C - HEAT PUMP CONTROLS & SWITCHES
AIR CONDITIONER COMPONENT PARTS
AIR CONDITIONER TYPES, ENERGY SOURCES
AIR FILTER EFFICIENCY
AIR FILTERS, FIBERGLASS PARTICLES
AIR FLOW MEASUREMENT CFM
APPLIANCE DIAGNOSIS & REPAIR
APPLIANCE EFFICIENCY RATINGS
BLOWER DOORS & AIR INFILTRATION
BLOWER FAN CONTINUOUS OPERATION
BLOWER FAN OPERATION & TESTING
BOOKSTORE - Air Conditioning "How To" Books
CAPACITORS for HARD STARTING MOTORS
CLEANING & Legionella BACTERIA
CHINESE DRYWALL HAZARDS
CONDENSATION or SWEATING PIPES, TANKS
DEFINITION of HEATING & COOLING TERMS
DEW POINT CALCULATION for WALLS
DEW POINT TABLE - CONDENSATION POINT GUIDE
DIAGNOSTIC GUIDES A/C / HEAT PUMP
DIAGNOSE & FIX HEATING PROBLEMS-BOILER
DIAGNOSE & FIX HEATING PROBLEMS-FURNACE
DUCTS - Asbestos
DUCT INSULATION, Asbestos Paper
DUCT INSULATION for SOUNDPROOFING
DUCT SYSTEM & DUCT DEFECTS
DUCT SYSTEM NOISES
DUCTS, Asbestos Transite Pipe
DUST, HVAC CONTAMINATION STUDY
ELECTRIC MOTOR OVERLOAD RESET SWITCH
EVAPORATIVE COOLING SYSTEMS
FAN LIMIT SWITCH
FAN NOISES, HVAC
GAS EXPOSURE EFFECTS, TOXIC
GAS DETECTION INSTRUMENTS
HEAT LOSS (or GAIN) in buildings
HEAT LOSS (or GAIN) INDICATORS
HEAT LOSS R U & K VALUE CALCULATION
HEATING SMALL LOADS
INSPECTION CHECKLIST - OUTDOOR UNIT
INSPECTION LIMITATIONS, A/C SYSTEMS
LEED GREEN BUILDING CERTIFICATION
LOST COOLING CAPACITY
LOW VOLTAGE TRANSFORMER TEST
MOTOR OVERLOAD RESET SWITCH
MOLD in AIR HANDLERS & DUCT WORK
OPERATING COST, AIR CONDITIONER
OPERATING DEFECTS, AIR CONDITIONING
REPAIR GUIDES A/C / HEAT PUMP
REPAIR & DIAGNOSTIC FAQs for A/C
THERMOSTATS, HEATING / COOLING
THERMOSTATIC EXPANSION VALVES
WATER COOLED AIR CONDITIONERS
WINDOW / WALL AIR CONDITIONERS
WINDOW / WALL A/C SUPPORTS
HVAC data tag decoding: This article explains and translates all of the data found on information tags and stickers used on air conditioning and heat pump equipment. This article series answers most questions about air conditioning systems.
This article provides help in decoding air conditioner, boiler, furnace, heat pump, water heater data tags and determining the age, model, or specifications of that equipment.
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Here we explain the meaning of each of the data names and contents of typical air conditioner system data tags. We include examples of how to make use of the data to estimate equipment age, capacity, and even its condition. (Not all of the terms we define below will appear on all equipment or motor tags.)
The photo at page top shows the main data sticker from a 1997 split system air conditioning compressor/condenser unit.
[Click to enlarge any image]
This model, made by Sanyo, Inc., provides easy-to-read basic data about the system including its year of manufacture, refrigerant, electrical requirements, and service information.
The photo shown here is for a conventional (non-split) residential air conditioning compressor unit.
Unless it has been painted-over or lost, on most air conditioners and heat pumps, a metal, foil, or plastic tag or data sticker is usually affixed to the outdoor air conditioner or heat pump compressor/condenser housing.
Depending on the age and equipment manufacturer the format and content of data on this tag varies, but typically the tag will allow you to discover some or all of the considerable amount of data listed here:
Modified, damaged, or torn air conditioning equipment information data tags can make age, capacity, and repair of any equipment more difficult. For the air conditioning compressor unit shown here, all we know is that the manufacturer was Singer. Model numbers and serial number appear to have been cut away from the data tag. Why?
Sometimes when equipment data labels are removed or obscured a building buyer or a home inspector may raise a concern that the unit installed was different than that which the was ordered or that it is of questionable origin. On rare occasion that might be the case..
But Ratib Baker, a member of member of Refrigeration Service Engineers Society (RSES), informs us that during the 1980's HVAC equipment manufacturers used a type of label which lacked UV resistance, faded, cracked, and eventually peeled away from the equipment, making equipment identification and ordering of replacement parts difficult.
Mr. Baker wrote (October 2008) that in the 1980's "the [HVAC compressor] label's protective mylar surface was damaged by the printing of the model and serial numbers and the electrical data which allowed the UV from the sun to destroy those areas. Upon discovering that they did not stand up to weather, most manufacturers started putting a second label inside the electrical compartment. Eventually better labels were designed, but some of the better manufacturers still put a second label in the unit."
Where a data tag or label on equipment is damaged or missing, check further for more label data including inside the unit's enclosure. Service technicians may have written the model and serial number data in indelible marker, or the manufacturer may have provided a second data label inside the unit - check HVAC equipment with lost or damaged labels to see if you can find that data elsewhere. You may also find equipment identification details in the installation and service manuals for the equipment if those have been kept in the building. Look around the indoor equipment for those documents.
What we can say from the label in the photograph above is that by 2007 when the photo was taken by an ASHI inspector, this particular equipment was at least 23 years old - older than its usual anticipated life expectancy: the Singer brand on air conditioners was dropped in 1984.
Where to Buy Carson Dunlop Associates' Technical Reference Guide decodes equipment data tags for air conditioners, heat pumps, etc.
Carson Dunlop Associates' Technical Reference Guide (below) provides the most extensive HVAC equipment data tag decoder & other information to determine the age of boilers, furnaces, water heaters, air conditioners, and heat pumps by decoding the product serial number.
For the most complete and very detailed HVAC equipment data tag and age decoding information anywhere (about 128 manufacturers & brands), Alan Carson and Bob Dunlop, of Carson Dunlop, Associates, Toronto, have provided us with (and we recommend) Carson Dunlop Weldon & Associates'
Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on any number of copies of the Technical Reference Guide purchased as a single order. Just enter INSPECTATRG in the order payment page "Promo/Redemption" space.
Here at InspectAPedia.com we discuss different types of heating systems (octopus furnaces, forced air heating systems, steam boilers, forced hot water boilers, high efficiency systems) and fuel types
(coal, oil, gas) as an aid in determining the age of a home or other building. Heat pumps are discussed at AIR CONDITIONING & HEAT PUMP SYSTEMS
The Carson Dunlop Technical Reference Guide provides both equipment data tag decoding data and also manufacturer contact information as well as historical dates for many brands of heating and cooling equipment. Included in the manufacturers listed are also makers of ancillary equipment such as controls, circulator pumps, etc., not just boilers, furnaces, and heat pumps themselves.
References for HVAC controls & switches
Whirlpool Corporation Equipment Data Tag Translator
Source: Whirlpool WGPH45 Packaged Heat Pump, Product Specifications 
[Click to enlarge any image]
Especially when equipment is old or has been located outside where its data tag can become obscured, faded, or damaged, it is easy to confuse as certain numeric digits some alphabetic characters, and vice versa.
Our table below gives some confusion examples to watch for. So if information about model numbers or serial numbers for a given manufacturer specifies that that company use a mix of alphabetic and numeric characters (E.G. General Electric), and you see only numeric, look again to see if you're making a mistake.
Service and refrigerant connections
Service information and/or refrigerant piping hook-up may be provided by a separate sticker on the air conditioner compressor/condenser unit, such as the piping arrangements shown on this split-unit compressor side.
More critical service data such as refrigerant type and operating pressures are recorded in the main data tag shown earlier.
Air conditioner or heat pump basic wiring diagrams
A basic hook-up wiring diagram may be provided by the manufacturer on a separate sticker on the air conditioner compressor/condenser unit such as this one from the Sanyo unit.
Air conditioner or heat pump safety warnings
Safety warnings for consumers and service people also appear on tags or stickers on modern air conditioning and heat pump units, such as shown in the photo above.
Data information tags on commercial air conditioning and heat pumps
Commercial air conditioning or A/C/Heat pump units such as the rooftop unit from which these data tag photos were taken often provides additional and critical capacity and service data.
[Click to enlarge any image]
The first or left hand tag shows the equipment's operating capacity in both BTUH and watts, and shows a maximum air temperature at the unit. The second photo at right shows a refrigerant charging chart that must be consulted by the service technician who monitors suction line (low pressure or return line) temperature and pressure.
Examples of HVAC Data Tag Decoding & Identification Questions
Reader Question: age of a GE air condenser unit
Could you help us determine the age of a General Electric central air condenser.
John, Carson Dunlop's Technical Reference Guide has several pages of GE equipment data decoding information, including the observation that
But the GE serial number codes on air conditioners & heat pumps used letters (N-Z = months Jan-Dec) and Year A-Y = 1944-1964, then repeated). Your serial number does not conform to the known codes for General Electric air conditioners. GE used letters not digits for month and year as I explained above.
Is it possible you are mis-reading a letter "Z" as a numeric "2" or a P or R as a "9" and an "S" as a "5" ?
Examples of troubles reading old fuzzy or partly obscured serial numbers or model numbers on HVAC equipment are in our article just above. So if your 2 and 5 are really SS the unit could be as old as May 1959 or perhaps more likely, as recent as 1980.
Send us a sharp focused photo of the entire label if you can and I'll comment further.
The Model Number you provided indicates in the two digits following the TA (TA36) 36,000 BTU/h
GE no longer makes A/C units - heat pumps were sold to Trane, Canada.
Reader Question: age & data tag decoding for Command Aire equipment
I am looking to replace a 30+ year old cooling/heating wall convector from a New York high-rise apartment unit.
Attached is the current unit in operation, and there a total of four (4) located in separate spaces within the unit.
[Click to enlarge any image]
Can you please tell me if you know what kind of a unit this is from the poor quality photo (Command-Air(?)), and if there are modern replacements I can look into that possibly can be controlled from a wall plate control next to a light switch (for example). - D.C. 8/21/2014
I'm not what I'm looking at in your photo.
But some basic information about wall convector units used for heating and/or cooling is at
Typically in a high rise apartment the energy source for heating and cooling will be piped from a common building source. You'll want to know what your building supplies before thinking about replacing the equipment.
The photo was a poor shot of the model label sent by the contractor currently remodeling the apartment. The units are enclosed within a built-in wooden lacquer cabinet, similar to the attached photos show. I was trying to make out the unit name, and I believe it is an early 80’s Command-Aire model, about 62” wide by 12” deep. I’ve also attached a stand-alone model, with the controls on top beneath the grill.
I’m not sure about the building supply details yet, since I have not received information from the contractor, but I’m just trying to find a comparably model to replace this unit(s). I believe the overall size and top diffuser gives me a head start to look into a Trane Type AK model, just to start comparing.
Command Aire brand was later bought by Trane - so when you know what type and model you've got installed that'd be a place to start looking for a compatible replacement.
When you have a clear image of the unit's data tag you'll see brand, model, serial number that will decode into just what is installed. There's little point in looking for equipment and prices before you know what kind of equipment works with your buiding's infrastructure.
Command Aire Data Tag BTUh Capacity Decoding
For example, Command Aire included heat pumps (which you may not have)
Contact Trane (commercial / residential) at
Continue reading at SEER RATINGS & OTHER DEFINITIONS or select a topic from the More Reading links shown below.
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