6876 0581/ 9272 6997 Office Address: 39 Woodlands Close #03-05 Mega@Woodlands

What is an ac condenser ?


An ac condenser is an outdoor unit which houses the compressor.  It is so known because it is normally placed in an open area or environment. The ac condenser is basically a machine playing the role of a heat exchange or heat transfer.  In fact, if you ever walk pass an operating ac condenser, you will feel very hot because of the hot air being blown out by the condensing fan.  Actually, it is advisable to place the ac condenser in open and airy area because it will help in facilitating its function of transferring heat to the outdoor environment.  Some people even try to place their ac condenser under shady areas in their garden. However, note that it is important to make sure the ac condenser is clear of any debris or rubbish which may obstruct its heat transfer.

How does the ac condenser transfer heat?


Heat is absorbed by the evaporating coil (also known as cooling coil) found in the indoor unit (also known as fan coil).  The heat absorbed by the evaporator coil is then transferred via the refrigerant in the aircon system to the ac condenser for dispersion.  The ac condenser has a condensing fan which serve the purpose of blowing out the heat to the outdoor environment at a faster speed.

What causes ac condenser to be so noisy?


When your air conditioning system is on, there bound to be a small amount of bearable sound coming out from the condenser. However, sometimes you may start to hear different types of loud, wierd and unusual noises coming out from the condenser.  When this happens, most likely certain key component in the condenser is malfunctioning. The different types of noises produce by the ac condenser provide useful symptom telling you which part of the condenser might have problem. Before we go into further details, lets understand what is an ac condenser made of first.

An ac condenser is made of the following key components :

  • Compressor(s);
  • Condensing coil;
  • Fan motor;
  • Refrigerant/Freon Gas;
  • Solenoid(s) and
  • Valve(s) (flow control device);

All the above components are integrated with inter connected electrical parts, piping and tubes.  The minute any of the above components becomes defective, the condenser will start to produce different types of strange noise. The character of each type of noise produced by the condenser provides an indication on which component is not working well.  Next, we will try to classify the different types of possible noises that a problematic ac condenser can produce.


What are the common noises produce by a problematic ac condenser?


The following are some common noises you may hear coming from a problematic ac condenser.  The noise includes but are not limited to the following:

a. humming – a low continuous sound
b. hissing – a sound like a long “s”
c. buzzing – a long continual sound
d. rattling – a short sharp knocking sound
e. banging – a sudden loud noise
f. clicking – a short sharp sound
g. screaming – very loud high-pitched sound
h. squealing- a long high-pitched sound

Why does ac condenser produces humming sound?


If your hears a loud humming noise (i.e. a low continuous sound)  from your AC condenser, the problem could be due to:

  • the compressor cushion has worn off;
  • the compressor internal component parts has worn out; or
  • the compressor capacitor has become faulty.
Solution:  Once you ascertain exactly which of the above part is faulty, replace it with a new part.  You can also source for a used part that is still working.  Once the faulty part is replaced, the humming sound should stop.

Why does ac condenser produces hissing sound?


If your AC condenser produces loud hissing noise (i.e. the sound of a long “s”), there are two possible causes.  First, it is likely that there is an internal blockage in the condensing coil.

Solution:  Clean the condensing coil and remove all the clogs and blockages.

If you have diligently cleaned away the dirts and clogs on the condensing coil but the hissing sound problem is still there.  The next possibility is that there is a leakage of refrigerant or the refrigerant valves may be damaged.

Solution:  Once refrigerant is involved, it is more advisable to engaged a professional to diagnose and solve the problem.

Why does ac condenser produces buzzing sound?


If your AC compressor produces loud buzzing noise (i.e. a long continual sound), it is an indication of a more serious problem. Either the motor, electrical component in the condenser has failed or the wire in the condenser has loosen.

Solution: Dealing with electrical components poses a higher risk and danger as there is a possibility of fire risk. Therefore in the event that your AC produces loud buzzing sound, we would recommend that you to contact a professional to help you solve the problem instead of fixing it by yourself.

Why does ac condenser produces rattling sound?


If the noise is a rattling sound (i.e. a short sharp knocking sound) , there are several likely causes.

First, most likely there is some problem with the condensing fan.  However, if the above effort does not solve the problem, there is a likelihood that the fan motor bearing is burnt out or the starting capacitor has become defective.

Solution1:  For condensing fan problem – normally cleaning the fan or re-aligning the fan will solve the problem.  For defective fan motor or starting capacitor – replace the defective parts.

Second, rattling sound from the condenser can also be caused either by loose parts, or shaking of the internal tubes.

Solution2:  Tightening the loose parts will solve the problem.

Third, rattling sound could also be due to the refrigerant level is too high or the wrong refrigerant type being used.

Solution3: If the problem is due to wrong refrigerant level or type, it is more advisable to engage an aircon professional to diagnose and solve the problem.

Why does ac condenser produces banging sound?


If the noise is a banging sound (i.e. a sudden loud noise), there could be loosen parts, i.e. piston pin, internal mount or even the crank shaft in the aircon compressor could have loosen. This could be an indication that the compressor lifespan is almost up.

Solution:  Replacement of compressor may be required.

Why does ac condenser produces clicking sound?


If your AC compressor starts to produce a persistent clicking sound (i.e. a short sharp sound), it could be due to loose parts or dirty fan.

Solution1: Tighhen the loose parts and clean the dirty fan.

If tightening the parts and cleaning the fan does not work, then there could be a bigger problem such as the followings:

  • control board is damaged;
  • thermostat wire is shorted; or
  • thermostat is broken.
Solution2: Handling the above components is very dangerous due to high risk of electrocution.  Therefore your should contact a professional to perform troubleshooting and help with the repair or replacement of parts.

Why does aircon condenser produces screaming sound?


If your AC compressor starts to produce unbearable screaming sound (i.e. very loud high-pitched sound) it is normally due to strong internal pressure due to a number of factors such as clogging, failed bearing or motor failure.

Solution:  It is advisable to engage a professional to troubleshoot and check which is the reason for the screaming sound.

Why does your ac condenser produces squealing sound?


If your AC compressor produces loud squealing noise (i.e.a long high-pitched sound) , either the fan motor or compressor motor is in trouble. This could be due to the air con being overused or the lifespan of the fan motor or compressor motor is nearing its end.

Solution:  Replacement of fan motor or compressor may be necessary.


Engaging a professional to help repair or replace your ac condenser


CitiCool offers free troubleshooting service to identify the problem existing in your defective ac condenser. However, we do charge a minimal transportation cost which can be used to offset against the repair cost. We also sell both used and new ac condenser component and parts that you may need to replace to fix your defective condenser. Customers who try to save cost normally choose to use used parts to replace the damage part of their condenser. If it is more cost effective to replace your ac condenser, we also have second hand ac condenser available for replacement. Normally, we would advise customer with an old aircon system to replace their condenser with a re-conditioned unit instead of a new unit. This is more cost effective because just in case the indoor unit also start to have problem later, the owner may consider changing the entire system. In this scenario, it may not be advisable to replace the current ac condenser with a new one.

Feel free to contact us if you require our service.

Other Related Educational Tips to read

Air Con System Components That Are Non Replaceable

Educational Content covering Causes, Tips and Solutions for Aircon Problems

Educational Content covering FAQ on Aircon Conditioner Problems 

Air Conditioning Service Office Contact


Tap the number below on your handphone to contact us.


Office Mainline No: . 6876 0581


Whatsapp No: 9272 6997


Check our office and aircon workshop location on our contact page.


Air Conditioning Service Booking





Find CitiCool on the following social media

To know more about CitiCool, join our social media:


Facebook : https://www.facebook.com/citicoolaircon


Google Plus : Google+


Twitter : https://twitter.com/CitiCool_Aircon