← Blog · By SK AC Service · 2026-09-28

AC Not Cooling? 7 Common Reasons and What to Do (Mumbai Guide)

An AC that runs but does not cool is one of the most common calls we get, often late in the evening when the heat is worst. Here are the usual causes, from easiest to most serious.

1. Dirty air filter

A clogged filter blocks airflow. Cleaning it takes 10 minutes; see how to clean an AC filter.

2. Dirty coils

Dust on the indoor or outdoor coil stops heat exchange. This needs a jet cleaning.

3. Low refrigerant (gas leak)

Weak cooling, ice on the copper pipe or a hissing sound point to a leak. Refilling without fixing the leak only gives temporary relief. Learn more on our AC gas filling page.

4. Faulty capacitor or fan motor

If the outdoor fan is not spinning or the AC hums and trips, the capacitor is a usual suspect. It is a quick, low-cost repair for a technician.

5. Wrong settings or sensor problem

Check that the mode is Cool, the temperature is set below the room temperature and the remote batteries are fine. A faulty thermistor can also confuse the AC.

6. Blocked drain or frozen coil

If water drips indoors or the coil turns to ice, switch the AC off and let it defrost before calling us.

7. Undersized AC or heat load

A 1 ton AC in a large, sun-facing room will struggle. Sunlight, many people and kitchen heat all increase the load.

Safety first

Do not open the outdoor unit or touch wiring yourself. If you see sparks, smell burning or the MCB keeps tripping, switch off the AC and call a professional.

We offer AC repair in Mumbai 24/7, including late evenings and holidays.

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AC Gas Filling and Installation: What Every Mumbai Homeowner Should Know