AC Not Cooling But Fan Is Running? Here's Exactly What's Wrong and How to Fix It in Kolkata
It is 2 PM in May. The temperature outside is 42°C. You walk into your room, switch on the AC, and the fan starts blowing — but the air coming out is warm. Not a little warm. Room temperature warm. You check the remote. 18°C is set. The display is on. The fan is definitely running. But your AC is not cooling at all.
If this sounds familiar, you are not alone. "AC not cooling but fan is running" is one of the most searched AC problems in Kolkata every summer — and for good reason. It happens to thousands of homes across Jadavpur, Garia, Tollygunge, Ballygunge, and Kasba every year between April and June.
The good news? This problem has a specific set of causes — and most of them are fixable the same day. This guide walks you through every possible reason your AC fan is running but not cooling, what you can check yourself in 5 minutes, and when you need a technician to step in.
Try these three things right now — they fix the problem in about 20% of cases:
- Check your remote — is the mode set to COOL, not Fan or Dry?
- Is the set temperature lower than the current room temperature? (Setting 28°C when the room is 27°C means the compressor won't start.)
- Check your MCB / circuit breaker — voltage fluctuations in Kolkata often trip the AC circuit. Reset it once and try again.
Why Your AC Fan Runs But Cooling Stops — The Real Reasons
When the fan runs but there is no cooling, it almost always means the compressor is not working — even though the fan motor is. The fan and the compressor are two separate systems inside your AC. The fan can run perfectly fine while the compressor is switched off, stuck, or failed.
Here are the six most common reasons this happens in Kolkata homes specifically:
Why Kolkata Homes Face This Problem More Than Other Cities
This is not just bad luck. Kolkata's specific climate and electricity conditions make the "fan running but no cooling" problem much more common here than in cities like Pune or Bengaluru. Here is why:
| Kolkata Factor | How It Causes This Problem |
|---|---|
| CESC voltage fluctuations (2–8 PM) | Daily voltage drops and surges stress the capacitor and compressor — causing early failure that makes the fan run without cooling |
| 7-month cooling season | Kolkata ACs run 1,700–2,000 hrs/year. Parts wear out 2–3 years faster than the national average, especially capacitors |
| 80–95% monsoon humidity | Accelerates corrosion on pipe joints and connections, creating refrigerant leaks that result in fan-only operation |
| Enclosed balconies and tight spaces | Outdoor unit overheating in narrow Kolkata balconies trips the compressor's thermal protection — fan keeps going, cooling stops |
What You Can Check Yourself Before Calling Anyone
Before picking up the phone, spend 10 minutes on these checks. They resolve the problem in roughly 1 in 4 cases — completely free.
This is the most embarrassingly common fix. Check the remote display — if it shows a fan icon or a water droplet icon instead of a snowflake, press the Mode button until you see the snowflake (Cool mode).
If the room is 32°C and you set 30°C, the compressor may not start — the temperature difference is too small. Set it to 18 or 20°C and wait 5 minutes to see if the cooling starts.
Open the front panel, remove the filters, and hold them under running water. A severely clogged filter reduces airflow so much that the coil freezes over — and a frozen coil produces zero cooling. This takes 10 minutes and costs nothing.
Go to your DB box and find the AC circuit breaker. If it has tripped to the middle position, flip it fully off, wait 30 seconds, then flip it back on. CESC voltage fluctuations trip MCBs regularly in South Kolkata — especially between 2 PM and 7 PM.
Go to your balcony or wherever the outdoor unit is. Is the fan on the outdoor unit spinning? Can you feel warm air coming out of it? If the outdoor unit is completely silent and still while the indoor fan runs — the compressor is not starting. This narrows it to a capacitor, PCB, or compressor fault — and you need a technician.
When to Stop DIY-ing and Call a Technician
Some AC problems genuinely need professional tools and certified skills. Here is a clear line between what you can do and what needs a technician:
One thing worth knowing: a good local technician in Kolkata will diagnose the problem first and tell you the cost before touching anything. If someone quotes you a price before even looking at the unit — that is a red flag worth paying attention to.
Teams like Unique Aircon — based in Jadavpur and serving South and Central Kolkata — arrive within 2–4 hours, inspect and diagnose first, quote transparently, and only start work once you have approved the cost. All repairs come with a 30-day warranty, which means if the same problem comes back within a month, they return at no extra charge.
What Does This Repair Typically Cost in Kolkata in 2026?
Knowing the rough cost helps you avoid being overcharged. Here is what each fix typically costs at a trusted local service in Kolkata:
| Cause of No Cooling | Typical Fix | Cost in Kolkata (2026) |
|---|---|---|
| Low refrigerant gas (top-up) | Gas pressure check + refill | ₹1,500 – ₹2,500 |
| Gas leak + full refill | Leak repair + vacuum + recharge | ₹2,500 – ₹4,500 |
| Capacitor replacement | Part replacement (20–30 mins) | ₹500 – ₹1,200 |
| Condenser coil cleaning | Jet wash of outdoor unit | ₹500 – ₹900 |
| PCB repair | Board repair or component replacement | ₹1,500 – ₹5,000 |
| Compressor replacement | Full compressor swap + gas refill | ₹7,500 – ₹18,000 |
Quick Answers to Common Questions
The Bottom Line
When your AC fan is running but there is no cooling, do not panic — and do not immediately agree to an expensive repair. Start with the five-minute self-check: mode, temperature, filter, MCB, and outdoor unit. These simple checks solve the problem about 20–25% of the time at zero cost.
If those do not work, the most likely culprits are low refrigerant gas or a weak capacitor — both of which are relatively affordable and quick to fix. The key is finding a technician who diagnoses before quoting and fixes it the same day.
For more on what different repairs cost, read our guides on AC gas refill charges in Kolkata and compressor repair costs — so you always know what a fair price looks like before anyone arrives at your door.
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