What Does Red and Green Light Blinking on AC Unit Mean?

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There are multiple reasons for your air conditioner flashing red light or green light. Different air conditioning brands may have different flash codes, which is why it is essential to safely store away your owner's manual when you first install your air conditioning unit for your reference.

Some codes are universal, such as a blinking red light which often indicates a problem with the internal mechanisms of your air conditioning unit. The flashing light informs you that the system has detected a problem that needs to be inspected immediately. Other light codes are as follows:

Causes of Red and Green Lights on Air Conditioner

Light Indicator Cause Explanation Solution
Solid Green Light AC is being turned on. A stagnant green light on your AC system simply means your air conditioner is running smoothly without any issues detected.
Solid Red Light The AC unit is being turned off. It indicates a system shut down if you press the power button on the control panel or remote control.
Flashing Green Light Only 1. Overvoltage
2. Issue with outdoor unit
3. Problem with the mode setting
Refrigerant leak
The flashing green light acts as a warning signal from the air conditioning to indicate various problems that need attention. These can range from electrical issues to mechanical problems or issues with the outdoor unit 1. Electrical Problems: Checking and fixing the electrical components or calling a professional.
2. Outdoor Unit Issues: Inspect the outdoor unit and clear any obstruction, or repair faulty parts.
3. Mode Setting Mismatch: Ensure all indoor units are set to the same mode setting.
4. Refrigerant Leak: Check for refrigerant leaks and repair them, followed by refilling the refrigerant to proper levels.
Flashing Red Light Only 1. Outdoor unit malfunction
2. Dirty air filter
3. Tripped circuit breaker
4. Other technical malfunction
Constant red flashing light may indicate a major problem that needs immediate attention. 1. Outdoor Unit Malfunction: Inspect the outdoor unit for debris and clear any blockages, additionally you might need to replace malfunctioning parts.
2. Dirty Air Filter: Clean the air filter and evaporator coils using soapy water and a vacuum.
3. Tripped Circuit Breaker: Reset any tripped breakers on the circuit board.
4. Other Technical Malfunctions: If the cause is unclear and the problem persists, contact the expert to diagnose the issues.
Flashing Both Green and Red Light Simultaneously - Clog in the condensor pipes
- A frozen AC
If your unit is flashing both red and green lights, then the issue is most likely with water flooding the system. This problem is often accompanied by water dripping out of your unit. Shut off the unit, and contact professional HVAC service providers to fix the issue immediately.

Troubleshooting Guide

Use Your Senses

A blinking light may or may not be a cause for alarm—it all depends on the brand and model of your unit. The best way to figure out if the flickering light is a cause for concern is to read the manual and use your senses.

See if the unit is dirty, listen for any strange noises, notice any foul smells, and check if the air coming from your air conditioning unit is warm, not cold. A flashing light combined with any of these symptoms indicates an underlying problem with your unit.

Clean the Air Filter

The air filter in the air conditioning unit works to trap dust, debris, and other particles to prevent them from entering the system. Over time, the filter can become clogged, reducing airflow and causing the system to work harder. Additionally, a dirty filter can also trigger blinking lights on the AC unit, as it affects the system's ability to circulate air properly. To avoid this problem, check the air filter regularly. If the filter is dirty, clean it or replace it with a new one.

Troubleshoot the Thermostat

The thermostat controls the temperature settings and operation modes of your AC unit. If it's malfunctioning or set incorrectly, it can lead to blinking lights on the unit. Ensure that the thermostat is set to the correct mode and temperature. If the thermostat is not responding or displaying incorrect information, it might be malfunctioning.

What you can do to solve this issue is to check the batteries and replace them. You should also ensure that the thermostat is correctly wired and there are no loose connections. If the thermostat continues to malfunction, consider replacing it with a new one.

Shut the Unit Down

When in doubt, shut the unit down, and unplug the aircon. This will avoid any further damage to your unit, and make it safe for you to inspect the interior. Even when your unit is working properly, there may be an issue that needs immediate attention in the inner workings of the unit.

Book Professional Service

The best way you can solve any aircon problem is by consulting with an experienced HVAC technician and booking their professional service. Our team at Luce is one of the best and most reliable HVAC service providers that you can find in Singapore. Whether you've lost your error code manual, or you can't make sense of the blinking lights on your AC, our professional technicians will be able to diagnose and repair the problem for you!

Aircon problems? Luce has got you covered! Give us a call today, and we'll get your unit up and running again in no time!

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