There are several potential reasons why an air conditioner (AC) may suddenly stop working after running fine for long hours. Some common causes include:
Thermostat Issue: The thermostat is responsible for regulating the temperature in the room and instructing the AC when to turn on and off. If there's a problem with the thermostat, it may not accurately sense the temperature or fail to send the proper signals to the AC unit, leading to unexpected shutdowns.
Overheating: Continuous operation of the AC for long hours can cause the system to overheat, especially if there are obstructions around the unit or if the outdoor condenser coils are dirty. Many AC systems have built-in safety features that automatically shut down the unit to prevent damage in such situations.
Electrical Problems: Issues with the electrical supply or wiring can cause the AC to stop working suddenly. A blown fuse, tripped circuit breaker, loose connections, or other electrical faults can interrupt the power supply to the AC unit.
Frozen Evaporator Coils: If the evaporator coils inside the indoor unit freeze due to reduced airflow or refrigerant issues, the AC may shut down to prevent damage to the compressor. Restricted airflow can occur due to dirty air filters, blocked vents, or malfunctioning blower fans.
Refrigerant Leak: A refrigerant leak can lead to reduced cooling capacity and cause the AC compressor to shut down to protect itself. Low refrigerant levels can also result in frozen evaporator coils, as mentioned earlier.
Dirty Condenser Coils: If the condenser coils on the outdoor unit are dirty or covered with debris, it can obstruct heat dissipation, leading to overheating and system shutdown.
Malfunctioning Compressor: The compressor is the heart of the AC system. If it develops a fault or stops working, the entire system may shut down.
System Age and Wear: Over time, AC systems may experience wear and tear, leading to the deterioration of components. Older systems may be more prone to sudden breakdowns.
If your AC suddenly stops working, the best course of action is to turn off the unit and contact a qualified HVAC technician to diagnose and resolve the issue. Attempting to troubleshoot and repair the AC yourself, especially if you are not familiar with HVAC systems, can be dangerous and may void any warranties you have on the equipment. Professional technicians have the expertise and tools to identify the root cause of the problem and perform the necessary repairs or maintenance to get your AC back up and running efficiently.