Why is My AC Not Cooling? (Detailed Reasons and Solutions)

Figure 1: Air conditioner indoor unit.

The air conditioner is a household appliance that we mostly use in the summer, and occasionally we encounter the problem of the air conditioner not cooling. So, why is the air conditioner not cooling? What are the reasons and the corresponding solutions for the air conditioner not cooling?

If the air conditioner is not cooling after it has just been installed, it is necessary to consider whether the air conditioner has quality problems. It is recommended to buy a first-class brand air conditioner, and the quality and after-sales can be guaranteed. It may also be that there is a problem during the installation of the air conditioner. In that case, you can contact the after-sales service in time for checking and repairing.

1. Reasons and Solutions for AC Not Cooling

The following are reasons why your AC is not cooling.

1.1 The Indoor or Outdoor Unit is Not Operating

When the air conditioner is not cooling, first check whether the air conditioner is operating normally, including the indoor unit and outdoor unit, especially the compressor of the air conditioner unit outside. As long as one of them is not functioning properly, then you have to call in a professional to repair it.

If the sound and the vibration of the air conditioner is relatively large, and the cooling effect is not good, you need to consider whether there is a problem with the air conditioner compressor (AC compressor). After the air conditioner is used for a long time, the AC compressor will also face aging, and the cooling capacity of the air conditioner will become worse and worse at this time. It is necessary to replace the AC compressor in time, otherwise it consumes more electricity and does not play the effect of cooling.

The line connection between the indoor and outdoor units is also one of the most frequent points of failure. If such a failure occurs, it is recommended to check whether the wire connection places are wrapped with waterproof insulating tape after connection.

Figure 2: Air conditioner indoor and outdoor units.

1.2 Air Filter Clogged

After the air conditioner has been used for a long time, it is necessary to clean the filter screen of the air conditioner and the dust on the indoor unit. These dusts affect the air intake, and at the same time also affect the cooling effect. After cleaning in time, it can be found that the cooling effect of the air conditioner is much better than before.

1.3 Heat Dissipation Problem of AC Outdoor Unit

The air conditioner unit outside has a radiator, which is responsible for exhausting the moisture and heat in the room. If the cooling effect of the air conditioner is not good, it may be that the outside AC unit is installed in a relatively closed space or the temperature around the outside AC unit is too high, causing the air in the small space where the outdoor unit is located not to circulate. So the heat from the radiator cannot dissipate, making the air conditioner not cooling.

Another possibility is that when the outdoor temperature exceeds 43 degrees, it is difficult for most air conditioners to transfer the indoor heat to the outside through the radiator of the outdoor unit, which will also cause the air conditioner to not cool.

At this time, it is necessary to clean up the dust and sundries around the outside AC unit in time, so that the air around the outdoor unit can circulate more easily or move the unit away from the high temperature environment.

1.4 Lack of Refrigerant

Insufficient refrigerant in the air conditioner is the most common cause of the air conditioner not cooling. When the refrigerant in the air conditioner is less than 20%, the cooling effect of the air conditioner is greatly reduced.

After confirming that the refrigerant is insufficient, please add appropriate refrigerant. You can contact the after-sales personnel to recharge the refrigerant.

Figure 3: Adding refrigeration for the air conditioner.

1.5 Pipeline Failure

If there are problems such as refrigerant leakage and insufficient refrigerant pressure in the air-conditioning pipeline, the cooling effect will also be affected. In this case, you need to contact professional maintenance personnel for overhaul and repair to solve the problem.

1.6 Low Supply Voltage

It may be that the supply voltage of the air conditioner is unstable causing the air conditioner not to cool. Generally, in summer there are peak periods of electricity consumption, during which the use of the air conditioner is prone to voltage instability, and this will also cause the air conditioner not to cool.

In such a situation, the better way is to increase the rated power of electricity by buying a voltage stabilizer.

1.7 The Power of the Air Conditioner is Not Enough

Insufficient air conditioner power is also a common reason why the air conditioner does not cool. If the air conditioner is working normally, and everything else is in good condition, but you feel no cold air in the room, and only when you are close to the air-conditioning outlet, can you feel the cold air, it may be because the horsepower of the air-conditioning is too small, and the space in the room is too large.

This requires the air conditioner designer to reasonably design the horsepower of the air conditioner according to the user's apartment size. In order to have a better cooling effect, it is best to properly over-allocate the cooling capacity.

Figure 4: Air conditioner compressors of different power.

1.8 Outdoor AC Unit Drain Pipe Clogged

When the drain pipe of the air conditioner unit outside is blocked, the water vapor cannot be discharged, and the air conditioner is naturally not cooling. At this time, the air conditioner can only be in the state of blowing air, but no cold air out.

1.9 The Airtightness of the Room is Not Good

If the airtightness of the room is not good, it will cause the hot air from the outside to enter the room, and the cooling effect of the indoor air conditioner will be slow. When turning on the air conditioner, please close the doors and windows, and if there is a room under direct sunlight, please install sunshade curtains.

1.10 Other Reasons

1. Pulling a vacuum before adding refrigerant is not done well, so there is moisture in the pipeline, and the moisture freezes in the pipeline, resulting in ice blockage and no cooling.
2. The capacitor of the AC compressor has poor contact or is damaged, causing the compressor not to work normally.
3. The control panel of the AC indoor or outdoor unit is faulty.
4. There is a problem with the temperature sensor in the indoor unit.
5. The connecting copper pipe is too long.
6. The fuse is blown.
7. Wrong wiring, etc.

Figure 5: Cleaning the air conditioner indoor unit.

In short, there are many reasons why the air conditioner does not cool, and you need to carefully investigate and solve it. In the process of using the air conditioner, you need to clean and maintain it regularly to avoid failures and to keep the normal operation of the air conditioner.

2. FAQs

2.1 Why is AC Not Turning on/ AC Unit Not Turning on?

If the air conditioner does not start, the first thing to check is whether the air conditioner power light is on normally.

The air conditioner power light is on:
If the power light is on, it means that the air conditioner is connected to the power supply normally, and there may be a problem with the remote control or components.

The air conditioner power light is not on:
If the power light is off, it means that the air conditioner is not powered on normally, so it cannot be started. The following reasons may cause the air conditioner to fail to power on.

1. The power plug is loose.
2. The power socket is not powered.
3. The air conditioner itself is malfunctioning.
4. The fuse in the special circuit of the air conditioner is blown.
5. If the power voltage used by the air conditioner is too low, the refrigeration compressor in the air conditioner will be difficult to start.
6. The high pressure relay operates. If the condensing pressure is too high, the high pressure relay operates to stop the operation of the compressor.
7. The low pressure relay operates. If there is insufficient refrigerant in the refrigeration system, the suction pressure of the compressor is too low, so that the low pressure relay operates to stop the operation of the compressor.
8. When the current of the AC compressor and fan motor is too large, the overload protection relay is activated to cut off the power supply.

2.2 Why is AC Blowing Warm Air?

If the air conditioner blows warm air, you can do the following:
·First check whether the air conditioner is in cooling mode.
·Confirm whether the air conditioner is a unit combining heating and cooling (heat pump type air conditioner). If so, check whether there is a problem with the four-way valve.
· If the air conditioner is a single unit that only has cooling function, it is impossible to produce warm air, and the worst situation is to blow out the air at room temperature.

2.3 Why is Air Conditioner Not Blowing Cold Air but Running (Air Conditioning Running but Not Blowing Cold Air)?

The following conditions may cause the problem that the air conditioner won’t blow out cold air when it is in normal operation:

·The refrigerant in the air conditioner is insufficient after leakage or the refrigerant is not added in time after long-term use;
·The power supply voltage is not enough, so the AC compressor cannot work normally;
·The cooling power of the air conditioner is too small;
·The external environment temperature is too high;
·The air conditioner is not cleaned and maintained for a long time;
·The copper pipe connecting the indoor unit and the outdoor unit is too long.

Related Info