Ten safe checks before you call an AC technician, and what not to touch

Before you book anyone, spend fifteen minutes on the checks below. They are all things you can do without tools and without opening anything that is meant to stay closed. If the AC comes back to life, you have saved a visit. If it does not, you will be able to describe the fault precisely, and the technician arrives knowing what to bring.

The rule for everything on this page: if a step involves the outdoor unit or any wiring, switch the AC off at its MCB first. Not the remote, not the wall switch — the MCB.

The ten checks

1. The remote. Mode on Cool (snowflake), not Fan or Dry. Temperature at 24°C or lower. Fan speed on High, not Auto. Timer and Sleep off. Fresh batteries. Many "not cooling" calls end here.

2. Power. Is the display lit? If not, check the plug, the wall switch and the AC's MCB in the distribution board. If the MCB is down, push it up once. If it drops again, stop and book a repair; do not keep forcing it.

3. Filters. Lift the front panel of the indoor unit, slide the filters out, hold them to the light. If you cannot see through them, rinse under a tap, dry in shade, refit. In a dusty locality or near a main road this is a monthly job in summer.

4. Airflow. Are the louvres open and moving? Is anything stacked on top of a window unit or in front of the indoor unit? Curtains draped over the grille are common.

5. The outdoor unit. Go outside and look. Is the fan turning when the AC is on? Are the fins matted with dust, leaves, a bird's nest or, near the coast, a white crust? Is anything stacked against it — gas cylinders, plants, a tarpaulin — blocking the air? Clear what you can reach without climbing on anything unsafe.

6. Listen. With the AC on, stand near the outdoor unit. A fan plus a deeper compressor note is normal. Fan only, or a hum that stops after a few seconds, means the compressor is not starting. Write that down for the technician.

7. The copper pipes. Look at the two insulated pipes at the outdoor unit. Heavy frost or ice on the thin one, or ice on the indoor coil, points to low gas or blocked airflow. Switch off, let it thaw for an hour, clean the filters, try again. If it ices again, book.

8. Water. If the indoor unit drips, check that the drain pipe outside is not kinked, crushed, or buried in mud. Water running out steadily while the AC is on is normal; water dripping inside is a blocked drain or a tilted unit.

9. Doors, windows and load. An AC that cooled the room fine last year but struggles now may simply have more to do: a gap under the door, a window left ajar, a new fridge or computer in the room, or a curtain that no longer blocks the afternoon sun on a west wall. At 42°C outside, these matter.

10. Time of day. If the AC works in the morning and fails only in the evening, note it. Evening voltage dips are common in Nellore in summer and a compressor may fail to start when the supply sags. That points to a stabiliser check, not a compressor replacement.

What you must not do

• Do not open the outdoor unit casing. The capacitor inside can hold a charge even with the power off, and the refrigerant circuit is sealed for a reason.
• Do not touch the gas. No "top-up" kits, no loosening of the flare nuts to "hear if there is gas". Refrigerant work needs gauges, a vacuum pump and the right gas for your unit; a refill on a split AC is ₹700 on the rate card and should only follow a leak check.
• Do not spray water on a running unit. Power off at the MCB first, and keep water away from the electrical box on the side.
• Do not use a pressure washer or a wire brush on the fins. They bend flat and the coil stops breathing.
• Do not bypass a tripping MCB or swap it for a bigger one. The MCB is protecting the wiring, not annoying you.
• Do not run the unit with ice on the coil. It will not cool any faster and can flood the indoor unit when it melts.

When to stop checking and book

Book a repair if any of these is true after the checks above:

• The MCB trips more than once.
• The outdoor unit does not start, or hums without starting.
• The coil ices up again after a thaw and clean filters.
• The display shows an error code or blinking pattern.
• There is a burning smell, a crackling sound, or the plug is hot to touch. Switch off at the MCB and leave it off.
• Cooling is weak even with clean filters and a clear outdoor unit.

A diagnosis visit is ₹350 and covers standard labour; a full service is ₹399. If the answer turns out to be a part, you see it and its MRP before it goes in.

What to say when you book

Three sentences are enough: what the air feels like, what the outdoor unit is doing, and when it started. If you noticed it only in the evenings, or only on very humid days, say so. That detail often decides what the technician brings.