Air conditioner breakdowns can quickly turn a pleasant summer into a nightmare. Whether you are a private individual or a professional, understanding common and frequent air conditioner problems can help you react quickly and avoid costly repairs.
In this article, you will find the most common faults, their possible causes and solutions for repairing them.
Before repairing, learn how an air conditioner works!
An air conditioner is a device designed to regulate the temperature and humidity of an indoor space. It works on a thermodynamic principle: it captures the heat present in the ambient air and expels it outside. This process cools a room in summer.
- The warm ambient air is absorbed by the refrigerant contained in the unit.
- The evaporator heat exchanger transfers the refrigerant to the air.
- A phase change then occurs: liquid, gaseous, then both.
- The compressor increases the pressure and temperature of the gaseous fluid.
- The pressure regulator reduces this pressure before the liquid is discharged into the condenser.
90% of breakdowns can be explained once you understand how an air conditioner works!
Top 6 air conditioner faults + Quick solutions
Why won't my air conditioner turn on?
Your air conditioner may not be turning on due to a power outage. A blown fuse may also be the reason why your air conditioner is not turning on.
As a solution, we suggest checking the circuit breaker or the socket. Change the batteries in the remote control.
If the air conditioner never turns on, turn off the power supply, locate the fuse (usually found in the fuse box or on the circuit board), check the condition of the fuse and replace it if necessary.
Why is my air conditioner leaking and leaving puddles of water?
If you notice that your air conditioner is leaking and leaving puddles of water, this is caused by water flowing inside and not draining away due to a blocked drain. Or it could be due to a problem with the condensate pumps, which means that the pump is not draining the water and the air conditioner starts to make unusual noises.
To combat this problem, the filters should be cleaned or replaced (every 2 months).
Switch off the air conditioner for 2-3 hours to defrost.
Test the pump by pouring a little water into it and replace it if it does not work.
Why does my air conditioner switch itself off?
The air conditioner switches itself off due to:
- overheating.
- a power surge problem.
- a technical issue.
To resolve this issue, the following would be required:
- Allow the appliance to cool down.
- Clean the sensors.
- Check the power supply.
Why is my air conditioner making unusual noises?
Noise coming from the indoor unit of your air conditioner may be due to:
- a loose fan.
- a faulty lift pump that can generate vibration noises.
- clogged filters that force the system to work harder.
To eliminate these noises, we recommend that you:
- Tighten the metal parts.
- clean the inside.
- Lubricate moving parts.
Why does my air conditioner smell bad?
Does your air conditioner emit a musty, foot-like or burnt smell?
Most of the time, the odour comes from mould in the filters or ducts due to stagnant moisture, burnt dust or bacteria in stagnant water.
As a solution to this problem, we recommend that you:
- Clean the filters.
- Activate ventilation mode only for one hour to dry.
- Empty and scrub the bin with bleach.
- Vacuum the dust from the indoor unit.
- Switch off for 30 minutes if overheating.
Why is my air conditioner not cooling?
There are several reasons why an air conditioner may not be cooling properly:
- thermostat problem.
- incorrect operating mode.
- faulty internal component.
You should always:
- Check whether your air conditioner is set to “cold” or “cool” mode.
- check for leaks.
- refill the gas.
- Check that the thermostat is working properly and is set to the correct temperature.
Preventative advice
- Clean the filters every 2 months.
- Schedule annual maintenance by a professional.
- Avoid extreme temperatures (maximum 5–7°C below the outside temperature).
When to call a professional?
- For gas leaks, electrical faults, or compressor issues.
- If the fault persists after basic troubleshooting.
Need specific help? Describe your breakdowns in the comments!
This post is also available in: Dutch French
