Power cuts are a common occurrence across Chennai — and when power returns, some ACs refuse to start. Before calling a technician, work through this checklist. Most post-power-cut AC issues are resolved in under 5 minutes without any tools.
Step 1: Wait 3–5 Minutes Before Restarting
This is the most important step that most people skip. When power is restored after a cut, the voltage often fluctuates for 1–3 minutes before stabilising. Starting an AC compressor during voltage fluctuation can trip the thermal protection switch — a built-in safety mechanism that cuts power to the compressor to prevent damage.
Switch the AC on only after the lights and fans in your home are running stably — this indicates normal voltage has returned.
Step 2: Check the Circuit Breaker or MCB
Power surges during restoration are common in Chennai and frequently trip circuit breakers. Go to your electrical distribution board (DB board) and look for a switch that has flipped to the middle or "off" position. This is the tripped MCB.
Fix: Push the switch fully to "off" first, then firmly back to "on." Try the AC again.
If the MCB trips again as soon as the AC starts, there may be a wiring or compressor issue — call a technician at this point.
Step 3: Check the AC's Internal Reset
Many modern ACs — especially inverter models — have an internal protection mode that activates during power fluctuations. The AC will not start until this resets. Signs include the power LED blinking but the unit not starting, or a "protection" indicator on the display.
Fix: Switch off the AC using the remote. Then switch off the AC's dedicated power switch on the wall (or unplug it). Wait 60 seconds. Then switch it back on. This performs a hard reset and clears the protection mode in most cases.
Step 4: Check the Remote and Batteries
Sometimes the issue isn't the AC — the remote's settings were lost during the power cut, or the batteries died. Check that the remote display is lit and showing correct mode and temperature settings.
Step 5: Check for Voltage Issues in Your Home
If the fans and lights work but the AC doesn't start, the voltage may be too low for the AC compressor (below 180V for most ACs). In some Chennai areas, post-power-cut voltage is unstable for 15–30 minutes.
If you have a voltmeter or a smart plug with voltage display, check the reading. If it's below 200V, wait for voltage to stabilise before starting the AC.
When to Call a Technician
Call a technician if:
- The MCB trips every time the AC is switched on
- The AC starts but immediately shuts down with an error code
- You notice a burning smell when the AC tries to start
- The outdoor unit makes a loud clicking or buzzing sound but the compressor doesn't run
- The AC was working fine before the power cut but now shows an error code
Power surge damage — most commonly a blown capacitor — is a quick and affordable repair. A capacitor replacement typically costs ₹500–1,500 and takes under 30 minutes.
How to Protect Your AC from Power Surge Damage
Consider installing a voltage stabiliser for your AC. A good stabiliser (₹1,500–3,000) protects the compressor from high and low voltage fluctuations — common in Chennai neighbourhoods with older infrastructure. This is especially recommended for premium inverter ACs.
RK Aircon provides same-day diagnosis and repair for post-power-cut AC issues across all Chennai neighbourhoods. Most surge damage repairs are completed in a single visit.