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Air Conditioning & Heat Pump Data Tags De-Coded AirCondAPedia © Enter your search terms Submit search form   Search This Website - InspectAPedia.com

• How to read & translate A/C & heat pump data tags & stickers
• Air conditioner electrical requirements
• Air conditioner refrigerant needs
• Air conditioner cooling capacity coded in model numbers
• Air conditioner and heat pump manufacturer's information

This article explains and translates all of the data found on information tags and stickers used on air conditioning and heat pump equipment. This website answers most questions about air conditioning systems. Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution. © Copyright 2008 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use the links at page left to navigate this document or to go to Other Website Topics. Green links at left show where you are in our document & website.

A/C DATA TAGS - Air conditioner & heat pump data tags

The photo at page top shows the main data sticker from a 1997 split system air conditioning compressor/condenser unit. 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:

• Manufacturer: The air conditioning equipment manufacturer
• Model Number, Serial Number, and Cooling Capacity: sometimes cooling capacity is coded into the model number but on most newer units including the Sanyo compressor shown here, oooling capacity is stated explicitly. On older equipment the BTUH cooling capacity may be encoded in the model numbers. [RATED COOLING CAPACITY discusses how to read the cooling capacity in BTUH or tons from air conditioning or heat pump tags and Carson dunlop at Technical Reviewers provides a manual that decodes more of that information.]
• Voltage or VAC for the compressor and separately for the blower fan. In addition to specifying voltage, the cycles (50HZ or 60HZ) and current phases (typically one phase for residential equipment) may be specified.
• Branch Circuit Selection Current- BCSC: recommended for determining the required size of the branch circuit conductors (wiring) supplying the equipment.
• Locked Rotor Amperage - LRA specifies the minimum circuit breaker or fuse size required and is the maximum current that the motor will draw when the motor's rotor is unable to move [locked]. [NEC Table 430-152-A]
• Minimum Circuit Ampacity - MCA: MCA can be used to determine the required size of branch circuit conductors (wiring and also control switches) supplying the equipment. [For example, using NEC Table 310-16 in the 60 degree column as required in 110-14]. However some experts recommend using BCSC. [Using the "minimum permitted" sized wire rather than the optimum-size to a compressor may save a few dollars at installation but may increase system operating costs and it may be less safe than using a larger conductor.]
• Maximum Fuse or HACR type Breaker: specifies the maximum overcurrent protection or MOP to be used to protect the equipment. The permitted ampacity of the equipment electrical circuit protection (fuse or circuit breaker amps) expressed as MOP or Maximum Overcurrent Protection. If MOP is specified, the breaker or fuse protecting the equipment should match this number. [A hermetic compressor draws varying amounts of current as its internal pressure changes during operation. Current draw is higher when starting the motor, and highest if the motor is starting against its highest backpressure such as when a unit is turned off and then back on in the middle of operation. Because fusing an air conditioning compressor at the minimum level can result in blown fuses or tripped breakers during these intervals of heavy current draw during compressor startup, compressors are either protected by a slow-blow fuse or a somewhat larger than minimum circuit breaker.] On some older equipment MOP is not specified. Only in the case that MOP is not specified can the overcurrent protection required be determined by the alternative means: [RLA OR BCSC whichever is greater x 175%], or if the compressor keeps tripping that device or blowing that fuse, RLA x 225% might be used. The National Electrical Code (NEC) specifies the degree to which a breaker or fuse may exceed the RLA.
• Rated Load Amperage - RLA, also called Rated Load Current or RLC on some equipment. This is the manufacturer's anticipated load during normal usage. [Typically about 64% of the maximum load current. See NEC section 440-2.]
• Full Load Amps - FLA full load motor current draw, level at which the motor can be operated without damage.
• Maximum Continuous Current - MCC not usually supplied, this is the most current that the compressor can draw without being damaged. [Typically about 150% of RLA.]
• BTUH Cooling Capacity: The A/C system cooling capacity, either explicitly stated in thousands of BTU's (British Thermal Units) per hour (BTUH) or implicitly given by other data, or coded in the unit's model number.
• The month and year of manufacture, possibly also encoded in the unit serial number. Since the typical life of an A/C compressor is about ten years, one would like to know the probable age of the equipment.
• The Energy Efficiency Ratio of cooling equipment is basically the amount of electricity you consume to obtain a given amount of cooling ability. It's expressed as (KW per hour of electricity used) / Thousand BTUs - this number is probably not going to be found on the equipment itself but may be in its documentation. Also see SEER at RATED COOLING CAPACITY.
• Refrigerant type is shown somewhere on every air conditioner, heat pump, or other cooling compressors. The tag shown here notes that the system uses [the now obsolete] R22 refrigerant.
• Month and year of manufacture is shown either explicitly as on the Sanyo compressor data tag shown here or this data may be encoded in the unit's serial number. Carson dunlop at Technical Reviewers provides a manual that decodes more of that data.

Modified or deliberately torn air conditioning information data tags such as this one are pretty interesting. All we know is that the manufacturer was Singer. Model numbers and serial number were deliberately cut away from the data tag. Why? Was the unit stolen? Was the air condtioning system installed with a capacity different than that which the customer had ordered? Was the unit an old one and past warranty, or even a used one? Was the system modified to use a new refrigerant, leading the technician to remove old, obsolete charging data? That would be no reason to remove the electrical data. Was the service technician sick of arguing with the homeowner about the system specifications? We don't know, but this is an unusual and suspicious act that deserves some further checking.

More Reading

• Air Conditioning A/C System Operating Controls & Overcurrent Protection discusses the electrical power controls, fusing, fuse sizing, and amperage or current measurements on air conditioning equipment (in the section on "Safety Controls" on that page.
• CONTROLS & SWITCHES - Switches and Controls on a typical split system with indoor and outdoor components were listed in the first chapter at A/C COMPONENT LIST

Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

Other information tags and stickers on air conditioners and heat pumps

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. 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.

AIR CONDITIONING SYSTEMS Chapter Index

To continue reading this air conditioning inspection guide, use links to the document chapters at left or below. Links shown in green font indicate where you are in this document.

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