Troubleshooting Guide
An AC that will not turn on is especially alarming when Delhi temperatures are at their summer peak. Before you call a repair technician — and potentially wait hours during a peak-demand day — there are eight quick checks any homeowner can do in under 10 minutes. In our experience at Air Control, approximately one in five "AC not turning on" calls we receive across Delhi, Noida, Gurgaon, and Faridabad is resolved by the customer themselves after we walk them through these basics. Here they are.
The most common cause of an AC not responding is depleted remote batteries. Replace them with fresh AA batteries (ensure correct polarity) and try again. Also check that you are pointing the remote at the indoor unit's IR receiver window, which is usually on the bottom-right of the unit's front face. If you have a spare remote or a smartphone remote app, test with that.
Ensure the AC's power plug is fully inserted into the socket. Test the socket with another device (a phone charger, for instance) to confirm the socket itself is live. During Delhi's summer load-shedding periods, some circuits cut out without the MCB visibly tripping — this can leave an AC without power while other circuits in the room still work.
Find your home's distribution board (DB box) and check if the AC's dedicated MCB has tripped to the middle or off position. If it has, switch it back on once. If it trips again immediately, do not reset it further — there is an electrical fault and a technician is needed. In Delhi NCR, voltage spikes during load restoration after power cuts frequently trip MCBs.
Many AC installations include a separate isolator switch near the outdoor unit with an internal fuse. A voltage spike can blow this fuse without tripping the MCB. Switch off the isolator, check the fuse visually (a blown fuse has a broken wire inside the glass cylinder), and replace with the correct rated fuse. If you are not comfortable doing this, call us.
Switch the AC off at the wall socket or MCB, wait 30–60 seconds, then switch it back on. This clears any PCB software glitch or protection mode lockout (some ACs lock out after a power surge). After restoring power, wait 3 minutes before pressing "on" on the remote — many modern ACs have a 3-minute compressor delay protection on startup.
Confirm the remote is set to Cool mode (not Fan-only or Dry), and the set temperature is lower than the current room temperature. If the set temperature is already equal to or higher than the room temperature, the compressor will not engage even though the fan may run. Set the temperature to 18°C and try again.
If you can hear a humming sound from the outdoor unit but neither the compressor nor the fan starts, a failed start capacitor is the most likely cause. The capacitor provides the electrical surge needed to start the motor — when it fails, the motor attempts to start, hums, and stalls. Capacitor replacement requires a trained technician with the right tools. Do not attempt to open the outdoor unit yourself.
If the indoor unit display is blank despite power being available, or if it shows an error/fault code, the PCB (printed circuit board) may have failed — often caused by a voltage surge. Note down any error code shown (e.g., "E1," "F1," "H6") before calling Air Control — this code tells our technician exactly which component the unit has flagged as faulty, allowing a faster repair.
Call us immediately if: the MCB trips every time you switch the AC on, you smell burning from the unit, the outdoor unit makes a loud humming or banging sound without starting, or any error code appears on the display. These are signs of an internal fault that requires professional diagnosis — attempting further troubleshooting can make the problem worse or create a safety hazard.
Air Control has serviced 500+ "AC not turning on" calls across Delhi and Gurgaon. Our technicians carry multimeters, capacitor testers, and common spare parts (capacitors, contactors, fuses) for same-visit resolution in most cases.
If the AC has power but won't start, common causes are a faulty remote control, a failed start capacitor (you may hear a hum but no motor movement), a tripped thermal overload protector, or a damaged PCB. Check the remote first, then call a technician.
A repeatedly tripping MCB indicates an electrical fault — either in the AC itself (compressor short, PCB fault, wiring issue) or due to voltage spikes from Delhi NCR's power grid. If the MCB trips every time you switch on the AC, do not reset it repeatedly — call a qualified technician immediately.
Yes. Most modern split ACs have a voltage protection circuit that prevents starting if supply voltage is below approximately 170V. During summer peak hours in parts of Delhi, Noida, and Faridabad, voltage can drop to unsafe levels. A voltage stabiliser can protect your AC and allow it to start even during fluctuations.
If the display is on but no motors start, the most likely causes are a failed start capacitor, a stuck compressor contactor, or a PCB fault code preventing operation. Check if the unit shows an error code on the display — note that code and call Air Control for a same-day diagnosis.
Yes, a hard reset (switch off at the plug or breaker for 30 seconds, then back on) is safe and often clears minor PCB glitches. However, if the AC fails to start after a reset, or the MCB trips again, do not continue resetting — this indicates a genuine fault that needs professional diagnosis.
Air Control · Sant Nagar, East of Kailash, New Delhi · +91 93122 64832 · ajay@aircontrols.in