Why Does The Fan Keep Running on My Air Conditioner?

Figure 1: Enjoy the cold air of air conditioner.

Today, the air conditioning, as an electrical appliance that can adjust the temperature and make people feel cool is welcomed and loved by many people. When the air conditioner works normally, the HVAC fan will automatically turn on and off as the heating and cooling cycle turns on and off. But when you use air conditioning in summer, you may encounter such a situation that the AC fan has been turning all the time. Now let's introduce the reasons for it.

1.What Are The Reasons The Fan On Your Air Conditioner Keeps Running?

When your AC fan keeps running, it's a time to find what's happening about it. The following are common reasons for the continuous blowing of the fan.

1.1 Switch The Fan to "On"

If your fan is switched to the “on" position, it will continuously run. You should set it to the auto position, so it only runs when the HVAC unit is running. Once you fix this setting, your AC unit fan will shut off when it recognizes the desired room temperature.

Figure 2: Switch the fan to “on".

1.2 The Indoor Area is Large

The indoor area is large and the cooling capacity of the air conditioner is insufficient. So, it can only work continuously to try to keep up with the setting of the thermostat resulting in the continuous operation of the fan and blower.

1.3 The Temperature You Set is too Low

The temperature you set is too low and it needs to run until it reaches the set temperature.

1.4 The Ambient Temperature is too High or The Machine Power is too Low

The ambient temperature is too high or the machine power is too low to reduce the temperature, so it works all the time. This means that the whole system including the fan will run longer than usual to reach the set temperature.

1.5 Insufficient Cooling Capacity of Air Conditioner

It is related to the insufficient cooling capacity of the air conditioner, or the refrigerant leaks. After the cooling capacity decreases, it will work all the time if it cannot reach the set temperature.

1.6 Thermostat Failure

If your thermostat / temperature sensor does not recognize your home's indoor temperature, the fan and cooling system will operate when they should not. This means that you need to replace the thermostat.

Figure 3: A air conditioner suffered thermostat failure.

1.7 Short Circuit or Damaged Relay Switch

If the fan is the only device that operates when the AC unit is not running, the relay switch may have failed preventing the setting on the thermostat from communicating with the fan.

1.8 Wiring Problem or Short Circuit

Another reason may be the wiring problem or short circuit which makes the system unable to recognize the on and off signals.

2. What Should We Do When the Air Conditioner Keep Running?

Figure 4: Ask a professional personnel for help.

Try the following steps to solve the problem:

2.1 Set The Fan to “Automatic"

If the fan is set to “on",Please change the setting to “automatic" to make it run only when the air conditioner is running.

2.2 Turn The Fan Switch to "Off" and Return to "Automatic"

If the fan is not turned off even if you turn the switch to the "off" position, your system may need to replace the thermostat. You can ask a professional personnel to help replace the thermostat. For other problems that cannot be eliminated or solved by yourself, such as relay damage, wiring problem or short circuit, please ask them for help.

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