Home / Aircon problem guide

Aircon not cooling, leaking, smelling or noisy—what should you check?

The same symptom can have several causes. This guide separates safe observations a user can make from situations where the unit should be stopped and inspected by a technician.

Stop using the unit and get help if there is a burning smell, smoke, sparking, electrical crackling, water near electrical parts or a breaker that repeatedly trips. Do not open electrical covers yourself.

The aircon is not cold or cools slowly

First check the operating mode, temperature setting, and whether doors and windows are closed. Then look at the user-removable filter only if the manufacturer’s instructions allow it. Heavy dust can reduce airflow.

Note whether the airflow is weak, the unit cycles frequently, the outdoor unit is inactive, or indicator lights are flashing. These observations help separate airflow, coil, electrical, sensor, installation and refrigerant possibilities.

Do not assume “low refrigerant” from weak cooling alone. A healthy sealed system should not need routine refilling. If refrigerant is low, the reason should also be investigated.

Water is leaking

Turn the unit off and protect furniture or flooring. Observe whether the water comes from the indoor unit, pipe or wall, and whether it begins immediately or after some operating time. Do not push objects into the drain or open parts containing wiring.

Potential causes include drainage blockage, slope, insulation, assembly, ice formation and other faults. A short video showing exactly where the water appears is useful.

Musty or unusual smell

A musty smell often relates to moisture and buildup, but the source may be the drain pan, pipe, filter or surrounding environment. Stop the unit for a burning or unfamiliar chemical smell and request an inspection.

Explain whether the smell occurs only at startup, throughout operation or after rain, and include the date of the most recent cleaning.

Noise or vibration

Record a video and identify whether the sound comes from the indoor or outdoor unit. Scraping, impact, humming or vibration can involve moving parts, mounting, assembly or electrical components. Do not keep operating a unit if the sound rapidly becomes worse.

Will not start or stops frequently

Check the remote batteries, note any error code or flashing light, and see whether other electrical circuits in the property work normally. If the breaker trips, stop resetting it. Repeated resets may be unsafe and can make the original fault harder to observe.

Information to send the technician

  • Safe photos of the indoor unit, outdoor unit and model label
  • Video of the symptom, sound, flashing light or water location
  • When it started and whether it is constant or intermittent
  • Recent cleaning, repair, relocation or installation history
  • Property type, unit count and location pin

Good information does not replace an on-site diagnosis, but it helps the team prepare the right questions, equipment and assessment scope.

Does it need cleaning or repair?

If the main problem is visible dust, weak airflow or a musty smell, cleaning may be part of the solution. Electrical faults, frequent shutdown, refrigerant problems, controls and damaged components need separate diagnosis. Do not select a cleaning package only because it is cheaper when the symptoms indicate another system.

Send the symptoms for an initial assessment

Photos, video, model, recent service history and location make the first conversation more useful.

CallLINEWhatsApp