In Singapore, where air conditioning is essential due to the sweltering tropical heat, it can be frustrating when we encounter problems with our air conditioner. One of the common aircon issues is the unit refusing to turn on as this issue could lead to higher electricity bills and unnecessary wear on your unit. But what if the air conditioner refuses to shut off instead?
Here are the 5 common reasons why your air conditioning unit won't turn off, and what you can do about them!
5 Reasons Your AC Won't Turn Off
Reason #1 Set Temperature is Too Low
Many Singaporean homeowners set their AC temperature to the lowest setting (e.g., 16°C) to cool their homes quickly. However, this can cause the unit to run continuously, as it struggles to reach a temperature that might be unrealistic given Singapore’s humidity and insulation levels.
We always recommend our client to set the thermostat to a moderate temperature, such as 24°C–26°C. This ensures energy efficiency while keeping your home comfortable.
Reason #2 Fan Limit Switch
The fan limit switch controls when your AC’s blower fan turns off. If it’s faulty or incorrectly set, the blower might continue running even after the cooling cycle has ended. This is a common issue in older HDB flats with aging aircon units. Always check your AC settings to see if the fan is set to “Auto” instead of “On.” If the problem persists, you may need a technician to inspect or replace the fan limit switch.
Regular aircon servicing by Luce can prevent such malfunctions!
Reason #3 Control Panel Has Low Batteries
When their air conditioner won't turn off, many of our clients immediately assume that their unit is faulty. It can also happen due to one simple reason—your thermostat or remote may have low batteries.
Before calling in a professional technician, you should try to replace the battery in your thermostat or remote control first and test if the issue resolves. If the problem persists, consider upgrading to a smart thermostat that provides alerts when battery levels are low.
Reason #4 Dirty Condenser Coils and Filter
Singapore’s dusty urban environment can cause your AC’s condenser coils and filter to clog, leading to inefficiency. A dirty air filter restricts airflow, causing the AC to work harder and run longer than necessary. This is a common issue in landed properties near Singapore construction sites or along busy roads.
To ensure this problem doesn't occur, clean or replace your AC filter every 1-2 months, especially if you live in an area with high dust levels. Schedule professional AC maintenance at least twice a year to ensure your condenser coils stay clean and efficient.
Reason #5 Aircon is Too Small for the Room
Air conditioners have different cooling capacities, and using a unit with a small capacity to cool off a large room can cause the unit to malfunction, refusing to shut off as it has not adequately cooled the room. In this case, you may need to upgrade your model.
Check your AC’s BTU (British Thermal Unit) rating against the size of your room. If the unit is undersized, consider upgrading to a more powerful model.
What to Do When Air Conditioner Won’t Turn Off?
Change Thermostat Fan Settings
In many Singapore homes, aircon settings are left unchanged for months, leading to inefficiencies. If your fan setting is set to “On,” the AC fan will keep running even when cooling is not needed. What you should do is to set your thermostat fan mode to "Auto" instead of "On." This allows the fan to run only when the cooling cycle is active, preventing unnecessary operation.
Adjust Thermostat Temperature Settings
Singapore’s high humidity can make indoor temperatures feel warmer than they are. If your thermostat is set too low, your AC may keep running endlessly to maintain an unrealistic temperature. Set your thermostat to a reasonable temperature, such as 24°C–26°C. This helps balance energy efficiency with comfort, ensuring your AC runs only when needed.
Ensure Proper Air Flow
When airflow is obstructed, the air conditioner's efficiency decreases, causing it to run longer than necessary. A buildup of dirt on cooling system components forces the unit to work harder to achieve the desired thermostat temperature.
To resolve this, you should replace air filters regularly. We always suggest our clients change them monthly, especially if they have pets or live in an area with high pollution levels in Singapore.
Clearing debris from the condenser, condenser coils, and evaporator coils helps maintain optimal cooling. If you’re unfamiliar with cleaning these parts, it's best to hire an HVAC professional, as the process requires specialized tools and expertise.
Clean the Blower Fan and Fan Blades
Over time, dust and dirt accumulate on the blower fan and fan blades, causing reduced efficiency. This is particularly common in Singapore’s humid climate, where mold and dust buildup happen quickly. You should schedule regular aircon servicing to clean the blower fan and fan blades. If you notice a reduction in airflow, a technician can inspect and clean these components to restore efficiency.
Got Aircon Problems?
For any aircon issues and problems, Luce is here to assist you. With decades of experience in Singapore’s aircon servicing industry, we provide our clients with top-notch services—from purchasing and installation to maintenance and repairs.
Give us a call today, and one of our helpful technicians will be able to help you with any aircon issues!
Check out our article about aircon fan not working!
