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Getting To Know Your Aircon Unit Capacitor

What is an aircon capacitor?

The capacitor is an essential component of the aircon compressor. An aircon capacitor is a device that stores energy and regulates the amount of power it gives off. Aircon units use this device to allow for a smoother transition from one temperature setting to another as well as faster cooling times. The aircon capacitor of each unit is different depending on the make and model, but more or less they are usually rated around 200-300V (Some may go up to 450V). They function as capacitors in that they temporarily store electric energy.

What does an aircon capacitor look like?

The color of each brand’s capacitors may be different (black, blue, grey), but mostly they have shiny silver metal casings with a black wrapping on them. The same goes for most brands’ fans which are metallic in color.

What does a faulty capacitor look like?

A faulty capacitors’ looks vary on different models. But as long as it’s bulging and swelling, the inside could be broken or leaking. This is usually the first sign that you need to change your capacitor. You can also read its value (uF/KVAr) which will tell you more about its condition and if it’s still working at its current state.

Why do you need to change your aircon capacitor?

Most of the time, capacitors are changed because they have lost their capacity to store electric energy after long usage. It enables the equipment to function properly, and any malfunctioning or shutting down of your aircon unit is usually linked to some vital part that needs replacement like the capacitor, compressor, and piston rings.

Most people cannot determine what’s actually wrong with their aircon units first before changing any components that possibly could be at fault. Aircon units are relatively costly units so most aircon units that break down will cause us to work overtime just to get our money back lest we incur further losses due to unplanned downtime. It is also recommended to customers on some occasions to change some parts so as not to waste even more money.

Signs that your aircon capacitor is damaged:

1) The aircon unit was working fine but suddenly it stopped cooling even though the compressor is still running and you can feel warm air coming out from the vents.

2) The aircon unit was working fine but suddenly it stopped cooling even though the compressor is still running and now your electric bill skyrockets every month.

3) A bulged top on the surface of the capacitor means it has been overheating too much over time which will affect its overall performance making it unable to provide enough current needed for proper operation of central aircon unit compressor motor, thus causing the entire aircon unit not to function properly during operation while also shortening the capacitor’s life.

4) Your blower motor will not start up when turning the system on, the only thing that turns on with every turn of the aircon unit breaker is just your compressor making a humming sound but nothing else happen or the blower fan does not start rotating which results in cooling aircon issues thus causing discomfort inside the room.

5) The smell of hot burning insulation from your aircon unit’s coil or from the compressor itself when it starts up indicates that there is a particular aircon issue with the capacitor, when this happens it means that there is not enough current supplied by the capacitor in order to start up properly so the entire aircon unit will encounter a shutdown thus resulting in overheating and starting up again which produces a nasty smell inside your aircon unit.

Other facts about your aircon capacitor:

1) The aircon capacitor is not a filter or cleaner. It does not reduce the amount of ozone produced by the aircon unit. If there are high levels of ozone in your home, it is because your aircon unit was not installed correctly with proper ventilation. Your indoor evaporator coil and an outdoor compressor need to be connected with a proper-sized copper tubing, and the outdoor compressor needs to be located directly above the indoor evaporator coil.

2) Although the capacitor life span is typically around 8-12 years, it depends on several factors including power quality coming into your home, humidity levels where you live, how hot your area gets. During extreme weather conditions, you may need to replace your capacitor sooner than the warranty period, so keep this in mind if you are on a tight budget.

3) Outdoor units usually have more than one capacitor for many different reasons, but mostly due to the fact that these units are called upon to run simultaneously more often than an indoor unit (heat pump or air conditioner).

4) It is not uncommon for faulty capacitors to be blamed for other issues such as compressor failure due to low cycling or being locked up. If you have tried replacing your capacitors but are still having aircon issues then strongly consider testing your power quality using an amp meter while operating indoor/outdoor units.

5) When removing capacitors from an outdoor unit, take note that since the compressor terminals are operating at 240 volts there is potential for electrical shock depending on what you touch. If the capacitor is not being replaced with a new unit then it should be left in-situ to prevent loss of refrigerant due to any damage or leakage that may occur if attempted removal. In some cases, capacitors are mounted directly on top of either the compressor terminals or compressor, meaning you must remove this first before removing capacitors from an outdoor heat pump unit without risking injury.


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 the 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.

WhatsApp us at +65 9222 4141 for a transparent quotation and honest pricing for all your aircon needs or Call us at +65 9222 4141. We offer a fast and efficient service to serve any of your aircon needs!


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