Home AppliancesAir Conditioner

What Does “A2” Mean on Air Conditioner?

What Does “A2” Mean On Air Conditioner

An ”a2” on your air conditioner can be a confusing sight, and finding out what it means is tricky.

It can either be inscribed on the unit or in the name or appear on display as an error code. What does this mean?


If A2 shows up in the name or on the details panel of your air conditioner, this is a rating of its energy efficiency.

However, it is an error code if a2 appears on your unit’s display.

Common causes of the a2 error code include:

  • A frozen compressor.
  • An overheated compressor.
  • A clogged air filter.
  • A faulty thermostat.

In this article, we will cover the most common reasons for an a2 error code, how to eliminate them as a possibility, and how to solve each of them if it is a problem.

5 Reasons for an “a2” Error Code

Depending on the manufacturer of the air conditioner, the a2 error code can refer to temperature or circuitry problems.

Luckily, most of these causes can be eliminated before paying to have it professionally repaired.

1. A Frozen Compressor

A Frozen Compressor

Frozen compressors are very common in air conditioners that are overdue for service. When your air conditioner cools your home, the air inside the machine reaches low temperatures.

If water is present from a leak or excessive humidity, it can freeze key components such as the compressor.

When the air conditioner senses ice on the compressor, it will throw out an error code and enter “defrosting mode.”

Detecting the Issue

This issue should be pretty apparent if you open up the air conditioner. This is because ice and water pools will be present around the cooling mechanisms.

Resolving the Issue

You will want to let the ice melt first, then wipe up as much water as possible with a towel.

If this is a frequent problem, you should check the area around the air conditioner for leaks and test the humidity levels inside your home.

Repair any leaks you find, and consider getting a dehumidifier if you measure values exceeding 60% relative humidity.

2. An Overheated Compressor

An Overheated Compressor

Just as your compressor can get too cold, it can also get too hot.

Your air conditioner cools your home by removing heat from the air and shifting it to an external vent. If the heat isn’t being vented properly, the compressor will overheat and cause an a2 error code.

Detecting the Issue

This issue should also be pretty easy to identify. Your air conditioner may feel hot on the sides and will feel similar to opening an oven around the compressor.

Resolving the Issue

An overheating air conditioning unit usually needs a good clean and better ventilation.

Areas to clean include:

  • The compressor coils (see how to do that here).
  • The air filter.
  • The exhaust duct.
  • The exhaust fan.

If you suspect a lack of ventilation is the problem, try placing a box fan near the air conditioner or shifting furniture to increase the open space around it.

3. A Clogged Air Filter

A Clogged Air Filter

This problem crops up every couple of years if you aren’t regularly maintaining your air conditioner. It is often a precursor or underlying cause of the first two problems.

Detecting the Issue

If you suspect your air filter is to blame, open the cover on your filter and look at it. Your unit’s manual has detailed instructions on your filter’s location and how to access it.

A clean air filter should be white or creamy and free of debris. If your air filter appears dingy and full of dirt and hair, then it could be the problem.

Resolving the Issue

  • First, locate the type of air filter used in your air conditioner by bringing the old one into a parts store, locating the product number on it, or consulting your unit’s manual.
  • Once you know what kind of filter your unit uses, buy a new one. Many home improvement stores stock air filters, as do Amazon and Walmart.
  • Please turn off the power to the air conditioner by unplugging it and switching off the breaker.
  • Install the new air filter (usually pretty easy and involves setting it into the compartment).
  • Close the panel covering the air filter.
  • Please turn on the unit and test it for cooling ability.
  • Throw away the old filter.

4. A Faulty Thermostat

A Faulty Thermostat

Now that we’ve covered the temperature-related culprits, we must rule out circuitry problems.

A faulty thermostat can cause an ”a2” error code. Thermostats wear out over time, so this is an especially likely cause if your unit is over ten years old.

Detecting the Issue

This issue can be difficult to detect, but you can often do so by disconnecting and bypassing the thermostat.

  • Cut power to the entire circuit.
  • Open the thermostat cover to expose the wires.
  • Please take a picture of the wire setup to know how it was connected.
  • Disconnect each wire, not letting it fall into the wall.
  • Connect the Y and Rc wires (usually yellow and red).
  • Turn the power back on and try to run the air conditioner.

If the air conditioner ran without the a2 error after bypassing the thermostat, then the thermostat was likely bad.

Preventing Wires From Falling Into the Wall

When disconnecting the thermostat, the wires may try to snake back into the wall.

This is a big pain; you must open the wall to get them back.

To prevent the wires from retracting into the wall, you can wrap the wires around any nonconductive object that is too big to fit into the hole in the wall.

A pencil is a popular choice among electricians.

Resolving the Issue

You will need to replace the thermostat. When installing the new thermostat, connect the wires to the same terminals (the manufacturer should label them on the part or in an accompanying document).

The terminals are usually W, Y, G, Rc, R, and C. Y and Rc are for your air conditioner, while the rest are for your heater and fan.

5. A Wire Shorting Somewhere

A Wire Shorting Somewhere

If you still suspect a wiring problem after eliminating the thermostat, there is probably a shortage somewhere.

Shorts can be caused by leaks, aging wiring, or shifting in the house.

You can technically visually examine the wiring with a millimeter to locate the problem. Still, we suggest hiring a professional since it involves messing around with live wires.

What Is an ”A2” Rating on an Air Conditioner?

What Is An A2 Rating On An Air Conditioner?

The phrase “A2 rating” can be included in the model number of your air conditioning unit and inscribed somewhere on the specifications sheet.

An example of this is the Friedrich A2 Code AC. This is an indicator of the air conditioner’s energy efficiency.

A2 ratings are usually expressed in SEER (Seasonal Energy Efficiency Ratio). This number estimates how much energy the unit will use during summer conditions. The higher the A2 rating, the better.

The most efficient units will have an A2 rating of 20, while the least efficient units will fall at 10.


An ”a2” error code is often caused by an issue regulating the units’ temperature or a circuitry issue.

You should examine the compressor to determine if it is too hot or cold (then fix the reason), replace the air filter, and test the thermostat.

If none of these fix the issue, then it is likely the wiring, which should be handled by a professional.

Frequently Asked Questions

Can I Run My Air Conditioner With a Cover on It?

You will probably get an error if you forget to remove the cover before turning on the air conditioner. This is because the cover prevents proper unit ventilation and can cause a heat or moisture-related error code.

Leave a Comment

Your email address will not be published. Required fields are marked *