AC Repair Guide
When temperatures in Delhi NCR cross 45°C in May and June, a malfunctioning AC is not a minor inconvenience — it is a health emergency. Air Control has been diagnosing and repairing ACs across Delhi, Gurgaon, Noida, and Faridabad since 1987, and we have seen every possible reason an air conditioner can stop cooling. This guide walks you through the 12 most common causes, how to identify them, and what to do next.
Delhi NCR experiences some of the harshest summers in India. Outdoor temperatures regularly breach 44–47°C, humidity spikes during monsoon, and power fluctuations are frequent. This combination stresses every component of your AC — the compressor works harder, the condenser coil struggles to reject heat, and electrical components face voltage stress. Understanding this context helps you appreciate why what works fine in a milder climate may fail here.
Refrigerant — commonly R32 or R410A in modern split ACs — is the substance that actually absorbs heat from your room and transfers it outside. If the system has a slow leak or was never fully charged during installation, cooling capacity drops sharply. You may notice the room takes much longer to cool, or never reaches the set temperature. This is the single most common cause we encounter across all areas — Delhi, Gurgaon, Noida, and Faridabad equally.
The air filter traps dust, pollen, and pollution particles before they reach the evaporator coil. Delhi's high particulate air quality means filters get clogged far faster than the manufacturer's recommended cleaning interval. A blocked filter restricts airflow so severely that the coil cannot absorb heat from the room — the AC runs continuously but the temperature barely drops. Cleaning the filter every 2–3 weeks during peak summer is essential in Delhi.
The compressor is the heart of the refrigeration cycle. When it weakens, refrigerant cannot circulate at the pressure needed for efficient heat exchange. Signs of compressor trouble include the outdoor unit making a hard starting noise, tripping the MCB, or the AC blowing slightly cool (but not cold) air. Compressor replacement is expensive, but catching the problem early — before it fails completely — can sometimes allow a capacitor replacement to restore function.
The outdoor unit's condenser coil rejects the heat extracted from your room into the outside air. In Delhi's dusty environment, and especially in areas near construction zones in Gurgaon and Greater Noida, the condenser fins get coated with dust, cotton fluff, and debris. When airflow through the condenser is restricted, the system cannot dump heat efficiently and cooling drops dramatically. A high-pressure wash of the outdoor unit as part of annual servicing solves this.
Paradoxically, an AC can form ice on its indoor coil and still produce no cooling. This happens when airflow is severely restricted (dirty filter) or refrigerant is very low, causing the coil temperature to drop below freezing. Ice acts as an insulator, blocking heat transfer. If you see ice on the copper pipe connecting indoor and outdoor units, switch the AC off immediately and call a technician.
Sometimes the issue is not mechanical at all. A faulty thermostat or remote control may send incorrect temperature readings to the PCB, causing the compressor to cycle off prematurely. Check that the remote's temperature sensor is not blocked and that the set temperature is lower than the room temperature. Also ensure the mode is set to "Cool" and not "Fan Only."
Counterintuitively, too much refrigerant is as damaging as too little. Overcharging — which sometimes happens when untrained technicians top up gas without first measuring the existing pressure — causes liquid refrigerant to enter the compressor, leading to damage and poor cooling. This is why gas top-up must only be done by certified technicians using proper manifold gauges.
Start and run capacitors help the compressor and fan motors start and maintain speed. A weak capacitor causes the compressor to struggle to start (you may hear a clicking or humming sound from the outdoor unit), ultimately leading to reduced cooling or no cooling at all. Capacitor replacement is one of the most cost-effective repairs.
Delhi NCR is notorious for voltage fluctuations. These fluctuations stress the printed circuit board (PCB) that controls the AC's functions. A partially damaged PCB may allow the fan to run while the compressor does not engage, giving the false impression that the AC is "running" without cooling. PCB issues require professional diagnosis.
Even with a clean filter, dust and mould can accumulate on the evaporator coil over months of use. A coated coil cannot efficiently absorb heat from room air. Annual deep cleaning — which involves chemical washing of the coil — restores full cooling capacity. Air Control has serviced 500+ ACs in South Delhi and East Delhi alone where neglected coil cleaning was the primary cause of reduced cooling.
If your AC is correctly maintained but still cannot cool a room, the unit may simply be undersized. In Delhi, where roof heat load is extreme in summer, a 1-ton AC may be insufficient for a room it would handle fine in a cooler city. A proper heat load calculation ensures you have the right capacity.
The indoor unit should be mounted with a slight downward angle and with clear space in front for airflow. If furniture, curtains, or partitions block the unit's air throw, cooled air recirculates immediately without cooling the room. Check that nothing obstructs the front panel.
If these checks do not resolve the issue, the problem is internal and requires a trained technician with the right tools. Attempting to open the unit or tamper with refrigerant lines yourself risks voiding your warranty and causing expensive damage.
Air Control has operated from Sant Nagar, East of Kailash, New Delhi since 1987 — nearly four decades of experience with Delhi's climate, power conditions, and the full range of AC brands available in India. Our technicians are trained on Daikin, Voltas, LG, Samsung, Carrier, Hitachi, Panasonic, Blue Star, and all other major brands. We offer same-day service across Delhi NCR, with transparent pricing and a 90-day warranty on all repairs.
We have serviced over 10,000 air conditioners across Delhi NCR. Whether your AC is failing in Defence Colony, DLF Cyber City Gurgaon, Sector 62 Noida, or Old Faridabad — we reach you fast.
The most common reasons are low refrigerant gas, a dirty air filter blocking airflow, a faulty compressor, or a clogged condenser coil. In Delhi's extreme summer heat, condenser units placed in direct sunlight can also overheat and reduce cooling efficiency significantly.
Signs of a gas leak include warm air from the vents, ice formation on the indoor unit's copper pipe, a hissing sound near the unit, and unusually high electricity bills. A professional technician can confirm with a gas pressure test.
No. Refrigerant handling requires certified equipment and training. Incorrect gas charging can damage the compressor permanently. Always call a certified AC technician for gas top-up or leak repair.
Cost depends on the cause. Gas top-up (R32) typically costs ₹1,500–₹3,000. Filter cleaning is ₹300–₹500. Compressor replacement can range from ₹6,000–₹18,000. Air Control provides a transparent quote before any work begins.
Air Control offers same-day service across Delhi, Gurgaon, Noida, and Faridabad. Call +91 93122 64832 and a technician is typically dispatched within 2–4 hours of your call.
Air Control · Sant Nagar, East of Kailash, New Delhi · +91 93122 64832 · ajay@aircontrols.in