Why Your AC Might Stop Cooling
An AC that runs but does not cool is one of the most common appliance complaints in Mumbai during summer and monsoon. Before calling a technician, it helps to know which causes you can address yourself and which require professional service.
Dirty or Clogged Air Filter — Check This First
A clogged filter restricts airflow, reducing cooling efficiency dramatically. In Mumbai's dusty and humid environment, filters can get clogged faster than in drier cities.
- Check the filter every 2–4 weeks during heavy use
- Rinse the filter gently under running water and let it dry completely before reinstalling
- A visibly grey or brown filter is too clogged to function properly — clean it immediately
- After cleaning, the AC should cool noticeably better within one cooling cycle
Low Refrigerant (Gas Leakage)
Refrigerant is the cooling agent that circulates between the indoor and outdoor units. If there is a leak, the system cannot transfer heat effectively and cooling drops sharply.
- Signs: AC runs but room stays warm; ice forming on the outdoor unit; hissing sound near the indoor unit
- Low refrigerant is not a DIY fix — it requires a licensed technician to detect the leak, repair it, and recharge the gas
- Do not just "top up" gas without fixing the leak — the gas will simply escape again
Dirty Outdoor (Condenser) Unit
The outdoor unit expels heat from your room. If the condenser coils are covered in dust, grime, or leaves (common in Mumbai's monsoon), heat cannot escape efficiently and the AC underperforms.
- Keep 30–50 cm clearance around the outdoor unit at all times
- Rinse the outdoor coils with water annually — avoid high-pressure jets that can bend the fins
- Do not cover the outdoor unit with plastic sheets even during monsoon — it needs ventilation
Incorrect Mode or Temperature Setting
Sounds obvious, but check that the mode is set to Cool (not Fan or Dry) and that the set temperature is lower than the current room temperature. In Dry mode, the AC removes humidity but does not actively cool the air to the target temperature.
Undersized AC for the Room
An AC that is too small for the room will run continuously without ever achieving the set temperature. A 1 ton AC is suited to rooms up to ~120 sq ft; 1.5 ton suits 120–180 sq ft; 2 ton suits 180–240 sq ft in Mumbai's climate. If your AC is correctly sized and still underperforms, the issue is elsewhere.
Iced-Up Evaporator Coil
Ice forming on the indoor unit's evaporator coil prevents airflow and stops cooling. This usually results from a dirty filter, low refrigerant, or running the AC at very low temperatures in high-humidity conditions.
- Turn off the cooling mode and run Fan only for 30–60 minutes to allow the ice to melt
- Once thawed, clean the filter and restart
- If ice forms again quickly, call a technician — it likely indicates low refrigerant or a deeper issue
When to Call for Service
- AC makes unusual grinding, rattling, or hissing sounds
- Ice forms on indoor or outdoor unit repeatedly
- Cooling drops suddenly after working well
- Water dripping excessively from the indoor unit inside the room (not outside)
- Electrical trips or burning smell from the unit
Authorised Service in Mumbai
For genuine parts and trained technicians, always contact the brand's authorised service centre rather than roadside mechanics. Sony Mony Electronics in Borivali can assist with service referrals for all major AC brands we sell. Visit sonymony.co.in for more information or to shop for your next AC.