Air conditioners are not made to explode. Yet, on Feb 10, 2020, three people were injured in an air conditioner explosion in Old Dhalka's Islampur area. April 29 saw three people receiving burn injuries from an incident in a barbershop in Paltan.Earlier on August 5, 2019, four of a family from the city's Kathalbagan area sustained burn injuries as their home AC unit reportedly exploded. Meanwhile, death toll from Friday's explosion at a Narayanganj mosque reached 24 as of yesterday. There was a load-shedding in the area and it is suspected that air conditioners exploded on the ground floor of the mosque as soon as electricity returned. Fire officials now suspect accumulated gas from a leaked pipe line that runs beneath the mosque caused a fire that might have triggered the explosion. What is going on? Investigations are under way. ACs rarely just explode. But they can overheat and catch on fire. That fire could lead to an explosion of the pressurised gas.

How do they overheat?

1. DIRT: Dust, grime and mineral scales build up on the condenser coil which is the thing inside the AC that looks like a densely packed grill made of tubes and aluminium fins. Dirt reduces its ability to transfer heat outside. As a result, your AC will run constantly without shutting off.

2. FAULTY WIRING: Electrical fires result from bad wiring and sub-standard plugs, sockets and circuit breakers.

3. POWER SURGE: What we refer to as "voltage up-down" can cause your home electronics to break down. This is a common issue with the electricity supply in the country. The first sign is usually flickering lights followed by a rise of drop in voltage.

4. USING THE WRONG GAS: ACs requires particular types of gas depending on when they were made. The most popular gas (refrigerant) used to be Freon which is non-flammable but has a higher rating for contributing to global warming. Newer units (mostly post 2019) are made to use R410a which is called Puron and it is also non-flammable. Using the wrong gas for a system could lead to overheating and fires.

How to tell if the AC is faulty?

1. AC compressor never stops running. This will also happen if you have an open door or window or the room is far bigger than the ACs cooling capacity.

2. Any unusual noises such as squealing or grinding could signal worn bearings.

How to maintain an AC?

1. Keep the AC unit's air filter clean so it does not have to work extra hard to pull air. Dhaka's air is especially dusty.

2. A window unit should lean a little outside so that condensation water drains out quickly.

3. Never use an extension cord for an air conditioner because these cannot take the electrical load. An AC should be connected to its circuit.

How to safeguard from fires?

1. Unplug during storms

2. Inspect wiring to make sure everything is in order.

3. Include surge protectors to prevent excess voltage from causing fires. Modern building should theoretically be equipped with surge protectors that safely dispel excess current through a proper ground connection.

4. Connect via circuit breakers so that they shut off if there is a spike thereby protecting your electronic devices.

5. If you repair an older AC unit, make sure the correct gas is being used to refill.

Simply put, we can avoid such incidents if we set up an AC wiring properly, add excess-voltage safeguards and maintain it regularly.