Why AC Compressor Stops After Few Minutes: 7 Causes & Fixes

This article aims to demystify the reasons why AC compressor stops after few minutes.

Why AC Compressor Stops After Few Minutes
Image Source: Wikimedia Commons

Why AC Compressor Stops After Few Minutes: Identifying the Causes

Understanding why AC compressor stops after few minutes is essential for effective troubleshooting. Here’s an in-depth exploration of common causes:


Overheating is a primary cause of compressor stoppage. This can occur due to restricted airflow from a dirty air filter or condenser coils, insufficient refrigerant, or a malfunctioning fan. When the compressor overheats, its internal overload protector will shut it off to prevent damage.

Electrical Issues

Electrical problems can range from minor issues like a loose connection to major concerns like a failing capacitor or a malfunctioning contactor. These issues can interrupt the power flow to the compressor. This, in turn, can cause the compressor to shut down. Regular electrical maintenance can help prevent these problems.

Refrigerant Leak

A refrigerant leak can decrease the efficiency of your AC unit and lead to low pressure. This causes the compressor to cycle on and off frequently. Signs of a refrigerant leak include ice on the refrigerant lines, hissing sounds, or a noticeable decrease in cooling efficiency.

Thermostat Malfunction

An improperly calibrated or malfunctioning thermostat can cause premature stoppage of the compressor. It might misread room temperatures or malfunction due to electrical issues or battery problems.

Pressure Imbalances

Your AC system operates under specific pressure conditions. If the pressure is too high or too low, it could trigger safety mechanisms that shut off the compressor. Causes of pressure imbalances include blocked air filters, refrigerant issues, or malfunctioning expansion valves.

Frozen Evaporator Coils

Frozen coils can occur due to low refrigerant levels, poor airflow (often from a dirty filter), or a malfunctioning blower motor. When the coils freeze, the system can’t effectively remove heat from the air. This causes the compressor to overwork and eventually shut down.

Aged or Worn-out Compressor

Over time, compressors can wear out from regular use. This wear can manifest as difficulty in starting, frequent stopping, or reduced cooling efficiency. An aged compressor may require more power to operate. As such, it can be more prone to overheating and breakdowns.

Troubleshooting Your AC Compressor

Troubleshooting your AC compressor involves a systematic approach to identify and isolate the issue. Here are detailed steps:

Check the Thermostat: Verify that the thermostat is set to the correct mode (cooling). Also, ensure that the temperature setting is below the current room temperature. Inspect the thermostat for any signs of malfunction. This might be unresponsiveness or erratic temperature readings, which could indicate a need for recalibration or replacement.

Inspect the Power Supply: Examine the electrical panel for any tripped breakers or blown fuses. Ensure that the AC unit is receiving power. Inspect the wiring to the compressor for any visible signs of wear, fraying, or disconnections.

Examine the Compressor: Check the compressor for any signs of damage or wear. Listen for unusual noises like grinding or clanking, which might indicate internal mechanical issues. Check if the compressor’s fan is running properly and if the unit is excessively hot. Those signs can signal overheating.

Look for Refrigerant Leaks: Check the refrigerant lines and connections for any signs of leaks, such as oily residue or hissing sounds. A refrigerant leak can lead to low pressure in the system. This causes the compressor to shut off prematurely.

Assess the Airflow: Inspect the air filters, evaporator, and condenser coils. A clogged air filter or dirty coils can restrict airflow. That can cause the system to work harder and possibly lead to compressor overheating. Replace or clean the air filter and clean the coils if necessary.

Monitor Pressure Levels: If you have the capability, use pressure gauges to check the system’s pressure levels. Anomalies in pressure can indicate issues like refrigerant leaks or blockages in the system. However, this step often requires professional tools and knowledge.

You can get this BENTISM 4-Way AC Manifold Gauge Set from Walmart to test your system’s pressure levels.

If these steps do not pinpoint the issue, it’s advisable to contact a professional HVAC technician for a more comprehensive diagnosis.

Check out these other articles…

AC Compressor Noise When On: 7 Simple Steps to Fix It

AC Compressor Makes Noise When Clutch Engages: 4 Easy Fixes

AC Compressor Smoking When AC Is On: 5 Simple Steps to Take

Why AC Compressor Won’t Turn On: 8 Reasons & Easy Fixes

Why AC Compressor Gets Hot: 5 Common Reasons & Easy Fixes

Why AC Compressor Starts After 2-3 Minutes: Detailed Reveal

Why AC Compressor Takes Time to Start: Detailed Explanation

Practical Fixes for a Malfunctioning AC Compressor

After diagnosing the issue, here are some practical solutions you can implement:

Reset or Replace the Thermostat: If the thermostat is found to be faulty, resetting it might resolve the issue. If resetting doesn’t work or the thermostat is outdated, consider replacing it with a new, more accurate model. Programmable thermostats can offer better control and efficiency.

Repair Electrical Connections: Address any discovered electrical issues immediately. This includes repairing or replacing damaged wiring, capacitors, or contactors. Given the complexity and danger of electrical repairs, these should ideally be handled by a professional.

Seal Refrigerant Leaks: Refrigerant leaks should be repaired by a certified technician. The technician will not only seal the leaks but also recharge the system with the correct amount of refrigerant, ensuring optimal operation.

Clean or Replace Air Filters: A clogged or dirty air filter can significantly impact the efficiency of your AC unit. Regularly check and replace or clean the air filters to ensure proper airflow. This not only helps in preventing compressor issues but also improves the overall air quality in your space.

Thaw Frozen Coils: If the evaporator coils are frozen, switch off the AC unit to allow them to thaw. After thawing, investigate the cause of the freeze, which might be due to low refrigerant levels, a dirty air filter, or other airflow issues. Address these underlying issues to prevent future occurrences.

Compressor Replacement: If the compressor is old, severely damaged, or continually failing, replacement might be the most viable solution. Compressor replacement is a complex task that should be performed by a qualified HVAC technician. They will ensure that the new compressor is compatible with your system and properly installed.

While some fixes, like replacing air filters or thawing coils, can be handled independently, others require professional intervention. Regular maintenance and timely repairs can help extend the life of your AC unit and prevent issues with the compressor.

Leave a Comment