Why Does Your Aircon Unit Turn Off By Itself?

If your aircon unit is turning off by itself, then your aircon unit  may have one of the following problems:

  • Aircon unit is not getting enough airflow
  • Aircon unit is short cycling
  • Condensate line is clogged
  • Faulty Thermostat
  • Refrigerant levels are low

Problem 1: Aircon unit is not getting enough airflow

To properly cool your home, your air conditioner needs to bring in a steady stream of warm air from your home. If your aircon unit isn’t getting enough air, components like the blower will work harder to cool your home. Eventually, these components can overheat and shut down the aircon unit.

One of the biggest restrictors of airflow is a dirty air filter. Since all air that enters your aircon has to pass through the filter, if the filter is clogged with dirt, air can’t pass through. Check your air filter to make sure it’s clean. If you see that the filter is covered in dirt, replace it with a new one.

Other causes of low airflow include:

  • Blocked vents: Make sure all the vents in your home are open and unobstructed so air can easily enter the return vents and exit the supply vents.
  • Fan problems: If your blower fan motor is malfunctioning, then your aircon unit will have a hard time pulling in a sufficient amount of air. A professional will need to check the fan and possibly replace the fan motor if it’s broken.
  • Leaky ducts: You can have a professional inspect your ductwork to look for leaks or disconnected ducts.

Problem 2: Aircon unit is short cycling

Short cycling is when your aircon unit turns off, then turns back on quickly. This “off/on” cycle continuously repeats, which causes significant wear and tear to your aircon system and makes it difficult for your home to remain at a comfortable temperature.

Short cycling is caused by 1 of 2 problems:

1) Your aircon unit is too big for your home: An air conditioner that’s too big for your home will cool your home really fast, then shut itself off. 

2) The thermostat is installed in a bad location: If your thermostat is located near a window or where direct sunlight can hit it or under an aircon vent, then the thermostat can’t accurately detect the real temperature of the room. A professional will need to relocate the thermostat if this is the case.

If you recently installed your thermostat or aircon system, short cycling may be what’s causing your system to shut off by itself. Contact the HVAC contractor who installed your system to make sure the air conditioner was sized correctly and that your thermostat is in the proper location.

Problem 3: Condensate line is clogged

Your air conditioner absorbs moisture from your home’s warm air. This moisture is called condensation which drains out of your home via a pipe so it doesn’t leak into your home.

Sometimes dirt and debris can enter the condensate pipe and create a clog. Instead of draining outside of your home, this condensation backs up into a drain pan. If the water reaches a certain level, it can trigger a switch that will shut off your aircon unit.

You can try to clear the line yourself by going to the air handler or indoor unit and locating the condensate line which is usually a white PVC pipe. Remove the cap from the T-shaped part of the line and pour distilled vinegar into the line. Wait 30 minutes then flush the line with water.

If the clog persists or your aircon unit keeps turning off by itself, contact an HVAC professional for further assistance.

Problem 4: Thermostat is faulty

You can think of the thermostat as the “brain” of your air conditioner. The thermostat sends signals to your aircon system, telling it when to turn on and off.

Like all types of electrical equipment, thermostats can sometimes malfunction. The device itself could be causing errors or the wiring that connects the thermostat to the aircon unit can develop a short, causing the system to shut off when it’s not supposed to.

You should contact a professional to inspect the thermostat and replace any faulty wires.

Problem 5: Refrigerant levels are low

Refrigerant is the substance that cools your home’s air. If your aircon unit is low on refrigerant which means there’s a leak somewhere, then the resulting pressure change can trigger a safety switch that shuts down an important part called the compressor.

If your compressor shuts down, your aircon unit will stop cooling your home’s air. The compressor will turn back on once the pressure has returned to safe levels.

That said, you’ll need to have a professional check for leaks and add refrigerant to your aircon unit, or your aircon will keep shutting off by itself.

You may have a refrigerant leak if you notice signs such as:

About 338aircon.sg

It’s always a good time to talk about the common issues that aircon units have. This way, you’ll be able to spot if there are problems with your unit or not and prepare for its replacement accordingly. If you require our aircon servicing services, Whatsapp us at +65 9222 4141 for a fast and transparent quote.

338 Aircon Servicing Singapore provides an extensive range of Aircon Services including Aircon Servicing, Aircon Repairs, Aircon Installation of best aircon brands, Chemical Overhaul, Gas Top-up, Aircon Leaking Water, and Aircon Not Cold Fix and more. We have a team of professional technicians who are equipped with vast knowledge and experience in the Aircon industry. 

We have over 15 years of experience in dealing with aircon works and have completed thousands of aircon works for both residential (Landed, Condo, and HDB) and commercial. We are a highly recommended Aircon Company in Singapore, with many delighted customers and reviews over the years on Google and Facebook. 

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