Why Does My AC Compressor Shut Off After 2-3 Minutes?

Figure 1: AC compressors.

In the hot summer, the air conditioner is one of the necessary cooling appliances. When we use the air conditioner in normal times, we should perform maintenance on it from time to time, so as to reduce the failure rate. In the process of using the air conditioner, it is inevitable that there will be some minor problems. The most common problem is that the air conditioner compressor (AC compressor, AC unit compressor) suddenly stops automatically after a few minutes of starting and running. What causes the air conditioner compressor to stop automatically after 2-3 minutes of starting?

In fact, the air conditioner compressor will automatically stop and start again after working for a period of time, which is a normal phenomenon. Air conditioner compressors, like refrigerator compressors, work intermittently. But if the start-stop interval is too short, and the AC compressor stops before the room temperature reaches the required temperature, then there is a problem, which is generally called a short cycling failure of the air conditioner.

Below we will introduce some of the reasons that can cause the AC short cycling.

1. Compressor Failure

The AC compressor is damaged. If the compressor is abnormal during working, it will cause the air conditioner to shut down suddenly.

At this time, you can open the shell of the air conditioner, find the position of the compressor, and then use a multimeter to check the status of the compressor. After confirming the compressor is damaged, it is necessary to purchase a new original compressor in time to replace the broken one.

Figure 2: A compressor and a fan in an AC outdoor unit.

2. Motor Failure

The motor is faulty. Generally, within a few minutes after the air conditioner is turned on, the motor will start to run. If the motor fails to run at this time, the air conditioner will have a shutdown problem.

3. Refrigerant Leakage

Open the shell of the air conditioner, find the pipeline that transports the refrigerant, and observe whether there is any leakage. If there is a refrigerant leak, the compressor does not have enough refrigerant to compress, and the air conditioner shuts down.

4. Voltage Instability

The reason why the AC compressor stops after a while may also be caused by unstable voltage. This kind of situation is very common in real life, and most users have encountered it, especially during the peak period of electricity consumption, so it is best for users to avoid using high-power electrical appliances during the peak period.

At this time, you can install a voltage regulator at home, or turn off the air conditioner, and wait for the voltage at home to stabilize before using it.

5. Compressor Protection Device Trips

When the system pressure is too high, the current is too large, and the compressor is overheated, the compressor overload protection will trip.

Figure 3: Compressor overload protectors.

Causes and elimination of high pressure and overheating in refrigeration system:
1. Too much refrigerant. Properly reduce the amount of refrigerant.
2. Poor heat dissipation. Check the condenser to see if it is dirty. Besides, if the indoor filter screen is too dirty, the fan speed of the outdoor unit is too slow, or the blades are broken and deformed, all of which will cause poor temperature exchange of the air conditioner. In addition, this situation will also occur when the outdoor unit is exposed to sunlight for a long time, which affects ventilation and heat dissipation.

3. Blocked pipeline system. Judge according to the test results of the pressure gauge.
4. Dirty evaporator or filter. If the evaporator or filter has dust and scaling, clean them.
5. Lack of refrigerant. When there is a lack of refrigerant, the gas discharge temperature will overheat, causing the thermal overload switch to trip.

6. The overheating protection shutdown of the outdoor unit caused by the damage of the starting capacitor of the fan. When the air conditioner is turned on, observe whether the fan of the outdoor unit is running normally or the speed of the fan blades is slow.

6. A/C Mode Setting Error

Incorrect mode setting causes automatic shutdown. When the air conditioner automatically shuts down, first check whether the remote control display is in sleep mode. If it is set in sleep mode, the air conditioner will automatically stop running when the indoor temperature reaches the preset temperature. In addition, check whether the remote control of the air conditioner is set to the timer mode.

Figure 4: Use the remote control to set the air conditioner.

7. Short Circuit

If the air conditioner stops shortly after starting up, then the user can consider that the wiring is short-circuited causing the air conditioner to be abnormal. For this kind of failure, it is recommended that users find a professional electrician to check the wiring at home to see if there are any potential safety hazards.

8. Other Reasons

1. The control circuit board is faulty.
2. The temperature sensor is overloaded.
3. The power connection is loose, poor, etc.

9. FAQs

9.1 AC Keeps Turning on and off?

The main reasons for the frequent start-up of the AC unit compressor are:
·Discharge pressure is too high, and suction pressure is too low.
·The adjustment value of the high voltage relay is too low or that of the low voltage relay is too high.
·The air conditioner temperature is set close to room temperature.
·The heat dissipation of the outdoor unit is not good.
·There are bad contacts in the AC circuit, such as plugs, switches, etc.
·Problems with the circuit control board itself.

9.2 Air Conditioner Starts then Stops after Only a Few Seconds?

The reasons for the failure of the air conditioner compressor to stop after working for a few seconds are as follows:

Typical overload protection phenomenon. The compressor is difficult to start, the starting current is too large, and the overload protection switch automatically trips. For this fault, it is necessary to check whether the starting capacitor or the starting coil of the compressor is burned. Also check whether the compressor is stuck.

The power supply voltage problem. The high-voltage protection spring strip is in poor contact, and the thermal protection spring strip inside the compressor is in poor contact.

If the AC unit compressor stops immediately after starting for a few seconds, you can check the specific fault location according to the fault code, or the main control board of the air conditioner or the compressor may be damaged.

9.3 AC Compressor Not Turning on / AC Not Turning on?

There are many reasons why the air conditioner compressor will not start:
·The power supply voltage is too low.
·The power socket has poor contact or the plug is damaged.
·The fuse in the air conditioner is blown or broken.
·The sensing element of the thermostat is damaged or there is an open circuit or short circuit.

9.4 Air Conditioner Fan Keeps Running When Turned off?

Heat dissipation. At the moment of shutdown, although the compressor has stopped working, the high-temperature refrigerant discharged before the shutdown still needs to be dissipated, so the fan of the outdoor unit will continue to run for a period of time, and will stop after cooling down the refrigerant.
When shutting down, it is recommended to use the remote control to shut down the air conditioner first, and not cut off the power directly, so that the outdoor fan motor can be delayed to shut down for a period of time.

Avoidance of damage. It may be an operation mode deliberately set to prevent damage to the equipment caused by the sudden stop of the air conditioner. Generally, it will continue to run for about ten minutes after shutdown (the continuous operation time of large air conditioners after shutdown will exceed this value, such as central air conditioners and large floor air conditioners. ).

There may also be too much moisture in the control board circuit parts, causing some circuits to be conducted wrongly, resulting in misoperation of the subsequent element. If there is a relay in the control circuit, the relay contact may stick due to long-term operation, so that the subsequent electrical appliances are out of control.

9.5 Outside AC Unit Running but No Air Blowing inside?

Specific reasons:
·The filter screen on the return air outlet of the indoor unit is blocked by dust. After the air conditioner has been used for a long time, the filter screen will be stained with dust, which will make the air output from the indoor unit weak or not, just clean the filter screen.
·The blades of the circulation fan on the indoor unit are stuck by foreign objects.

·Lack of or leakage of refrigerant in the air conditioning and refrigeration system. When the refrigerant in the air conditioner leaks or is lacking, the indoor unit of the air conditioner will not blow out the air.

·The air conditioner has reached the set temperature. There will be no air blown out when the air conditioner reaches the set temperature.
·AC compressors, fans and capacitors are damaged.

Related Info