Common Aircon Unit Compressor Problems And How To Repair It

In some aircon units, especially the old ones, the compressor unit is usually placed outdoors. However, for smaller aircon unit models, it is usually placed within the condenser. An aircon unit and its compressor are usually combined into one sealed unit. The compressor has a motor that functions just like a pump that removes hot refrigerated gas and condenses refrigerant gas making it have higher pressure and a higher temperature.

Here are some FAQ about your aircon unit compressor:

How long do aircon unit compressors last?

The short answer is that your aircon unit compressor and refrigerant should last about 12-15 years. Learning what crucial components, and how to maintain the compressor, can keep your aircon unit running efficiently for its entire lifespan.

Is an aircon unit compressor worth fixing?

The compressor is an expensive item to replace. Because dead compressors usually happen in old aircon units, it’s more cost-effective to start over with a new aircon unit rather than pay to put a new compressor into an aircon unit that’s already wasting power and a few years from the junk heap

Can an aircon unit compressor be repaired?

Here’s the thing, you can’t repair an aircon unit compressor if it breaks down. The compressor of your aircon unit is essentially the heart of the entire aircon unit, responsible for allowing the refrigerant process that even makes it possible for your cooling system to cool.

In case a compressor fails, it will not be able to maintain pressure and temperature differences leading to malfunctioning of the entire aircon unit. Compressor problems are caused by different problems. 

Here are some common aircon unit compressor problems and their repair procedures: 

Compressor wiring issues

The compressor may sometimes have a symptom where it fails to run, though it could hum silently. This aircon issue could occur when the compressor wire breaks hence stopping the running of the compressor. If the wires of the compressor are open, it could lead to damage to the entire aircon unit. It is thus important to call for a professional aircon servicing company to repair it immediately to prevent further aircon issues. You can solve this aircon issue by opening the compressor and checking on its wires to ensure that they are well connected and function well.

However, if this is an aircon emergency, simply put off the compressor, remove the outer cover of the compressor then identify the wires within the thermal limiter. If you find this process somewhat sophisticated, you can find help from professional aircon servicing companies since this is their area of expertise. They will be able to open the compressor and find out if terminals allow the flow of electricity. 

Compressor starts but keeps failing 

At some point, the compressor may not start at all or may start for a short while but will keep failing. This aircon issue is usually caused due to defects within the motor. The motor can get defective in different steps; it gets worn out and the insulation within the windings is removed. After this, it burns and will stop working. Fortunately, if this happens the fuse will trip and will protect the whole motor and compressor. You can solve this aircon issue by finding a new fuse and replacing wires that were worn out. If this does not work, better call a professional aircon servicing company as it means that the motor burnt up beyond aircon repair. If this occurs, you may have to find a new compressor replacement.

Failure of the compressor to run

If you are keen enough, you will notice the temperature of your compressor rising to high levels, this eventually leads to overheating. Overheating is usually caused by different aircon issues. It can be due to poor wiring or the motor may not be functioning well. Repairing this is however quite complicated. Unless you fully understand the whole operation of your compressor, you may want to leave this repair to a professional aircon servicing company’s hands. 

Overheating and shutting down will be a different problem from simply overheating. In case this happens, you will experience alternating periods of little cooling, then no cooling whatsoever. This is usually caused by clogged coils. Clean your condenser coils severally then try to find out if this solves the aircon issue. If it does not solve the whole aircon issue, you may have to install a new filter. After this, open its supply vents to ensure that there is correct airflow through the compressor’s condenser coils.

The motor does not start 

We already know that the motor is responsible for most aircon issues within the aircon compressor. Sometimes, the motor fails to start at all leading to a general malfunctioning of the compressor. When this happens, it is usually due to a faulty capacitor known as the start capacitor. If you understand the functioning of the compressor well, a little replacing of the failed components will do the work, but if you find it complicated and you also lack the proper tools or equipment, better call a professional aircon servicing company for help and replacement of a new aircon unit capacitor. 

Compressor bearing failure (produces creaking sounds)

Though this is not very common, a bearing compressor could trigger further aircon issues within your compressor. If not solved it could trigger a more serious aircon issue that may cause a general failure of your aircon unit. You can know a bearing failure has occurred since the compressor will produce creaking sounds. These are sounds like that of a motor with a bad bearing. After some time, it may lock itself up and refuse to run. The moment you hear any such sounds, make sure that you find a bearing replacement for your compressor unit. If you leave it to run for an extended time, the rotor within the motor could wobble creating a failed short that could destroy the whole compressor. 

Mechanical failure of the compressor  

Your compressor could sometimes undergo a mechanical failure and fail to run completely. This happens when the compressor locks and causes a general switch off. You will know this since there will be a buzz quite loudly for some seconds and may finally shudder. If you decide to check on the compressor, you will not find any open or failed short.

In case the compressor fails this way, there are very few repair options you can consider. Replacing the whole unit will, therefore, be a viable option as long as the other parts of the aircon units are not old. Before conducting this replacement, it will be a better option to call a professional aircon servicing company to carefully inspect the entire aircon unit. This is in a bid to ensure that this aircon issue was not induced by other parts of the aircon unit

Worn out compressor

Sometimes, the compressor could be fully worn out, old and damaged. Replacing it will solve everything. The compressor comes with a serial number and a model number on its metal plate. Note these numbers and shop for compressors with this kind of plate. You can also replace your motor through your warranty. In case your motor malfunctions and its warranty is not expired, make sure that you first take it back to its manufacturer for a free repair or free replacement. The compressor performs the biggest role in the aircon unit process.

You should thus ensure regular aircon maintenance from your reliable professional aircon servicing company to have every part of your aircon unit work in perfect condition. Clean it regularly by removing any particles of dust that could attach to the compressor. If you experience any aircon issues, you can troubleshoot them with the above list to return your compressor to its previous normal condition.


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!