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Why Does My Air Conditioner Keep Running Nonstop?

Having your air conditioner continuously run all day and night is frustrating, worrying, and can significantly increase electricity bills. If your AC unit won’t shut off and cycles on and on relentlessly, something is wrong.

In this in-depth guide, we will thoroughly explore the top reasons behind air conditioners that run nonstop and how to diagnose the problem. With expertise from Turbo AC Repair’s seasoned technicians, we provide actionable solutions so you can resolve AC issues and keep your home cool during hot summers.

What Triggers an AC System to Run Nonstop?

Several possible causes lead to air conditioners endlessly running without ever shutting off:

Low Refrigerant Levels – The #1 Culprit The most common reason an AC unit cycles continuously without stopping is low refrigerant levels. Refrigerant is the chemical compound responsible for enabling cooling and heat transfer inside the AC system.

Over months and years, refrigerant slowly leaks out through small cracks, faulty seals, loose fittings, and small perforations in the refrigerant lines. This reduces the AC system’s total cooling capacity, forcing it to run excessively to try lowering the indoor temperature. In some cases, topping off the refrigerant resolves the issue, but any leaks should be located and repaired to prevent continued loss of refrigerant.

Dirty Air Filter Reduces Airflow If the AC air filter becomes excessively dirty or clogged with dust and debris, reduced airflow often occurs. This lowers system efficiency, making the AC work much harder to push enough cooled air through the ducts to lower your home’s temperature. The system may run continuously for hours attempting to compensate for reduced airflow through a filthy filter. Simply replacing a very dirty clogged filter can often fix nonstop AC operation in these cases.

Thermostat Problems Cause Chaos Issues with the thermostat, like improper calibration or failed sensors, can cause the AC system to get stuck running continuously even after the desired set temperature is reached. This nonstop operation occurs because the thermostat inaccurately reads the indoor temperature, thinking cooling is still needed. Carefully reconfiguring or replacing a problematic thermostat will stop the AC from running indefinitely.

Electrical Control Components Fail The various electrical components that control AC system operation like relays, contactors, capacitors, fuses, and circuit boards can fail or malfunction over time. This disrupts the proper on/off cycling of the AC system. For example, a stuck or welded contactor can force the AC compressor to stay powered on indefinitely. Electrical control repairs by a professional are needed to resolve these types of issues.

Oversized AC Unit Short Cycles A central air conditioning system that has far too much cooling capacity for your home’s size can lead to short cycling and excessive runtimes. It reaches the set temperature rapidly before shutting off, then restarts shortly after when indoor temps creep up a single degree. Properly sizing AC units to match the cooling loads needed for your home’s square footage improves efficiency and prevents problematic continuous operation.

Low Refrigerant Charge Makes AC Work Too Hard A refrigerant charge inside the AC system that is too low can force the unit to stay on constantly trying to cool your home. Topping off the refrigerant level to the factory specified amount will often fix this issue. Any leaks should then be identified and repaired to prevent the charge from dropping low again.

How to Accurately Diagnose Why an AC Runs Nonstop

Pinpointing the exact reason an AC system stays on indefinitely requires a thorough diagnostic process. Here are the most effective troubleshooting steps:

  • Verify Thermostat Settings – Check that the temperature setpoint is set below the current indoor temperature. The AC should not be running continuously if the set temp is higher than the ambient room temperature.
  • Inspect the Outdoor Unit – While the AC is running, listen and look for signs of normal operation versus problems. For example, frozen cooling coils indicate low refrigerant levels. Unusual noises can signify compressor failure.
  • Check the Indoor Filter – A filthy clogged filter prevents sufficient airflow and must be changed. Measure the temperature difference between air return and AC supply vents. A small differential usually signals reduced airflow.
  • Examine Electrical Components – Look for burnt contacts, loose wires, or blown fuses. Use a multimeter to check for abnormal voltage/resistance readings indicating issues.
  • Professional HVAC Diagnostics – Have an HVAC technician perform in-depth refrigerant pressure and electrical testing to determine if levels are within specified ranges. Advanced tools can detect very small refrigerant leaks.
  • Consider an AC System Replacement – If the AC unit is grossly oversized, have a contractor perform a Manual J load calculation to right-size your new system.

How to Repair an AC Running Nonstop

Once the root cause of the problem is found, the appropriate repairs can be made to stop AC systems from running indefinitely. Here are solutions to the most common issues:

Repair Refrigerant Leaks Pinpoint leak locations using dye injection testing. Carefully repair leaks and reseal cracked fittings, lines, valves. Then evacuate and recharge the system with the factory specified amount of fresh refrigerant.

Top Off Low Refrigerant Slowly top off the refrigerant if the level is slightly low using the R-22 or R-410A recharge procedures. Thoroughly check for leaks and repair any found.

Replace a Clogged Air Filter

Swap the filter out with a clean MERV 11-13 pleated air filter of the proper size. Upgrade to a washable electrostatic filter and remember to clean it routinely each month.

Install a New Thermostat Replace old inaccurate mechanical or digital thermostats with a new digitally programmable thermostat properly configured for your AC system. Recalibrate problematic smart WiFi thermostats.

Repair Electrical Control Components Replace failed control boards. Swap out malfunctioning contactors and relays. Verify electrical ratings match compressor. Check capacitor microfarads.

Right Size Your AC System Have a licensed contractor install a new, smaller AC system properly sized for your home’s cooling needs. It will run less frequently and have longer off cycles.

Add Refrigerant If Overcharged If overcharged, evacuate the excess refrigerant to bring the pressures and charge level back down into the specified range.

Trust Your AC Repairs to the Pros at Turbo AC

While AC problems like continuous operation seem intimidating, Turbo AC Repair has the skill, experience, and credentials to accurately diagnose issues and get your system running optimally again quickly. Our NATE-certified technicians are highly trained and equipped to service all makes and models.

For fast, effective solutions to any AC problem, contact our AC repair experts at (281) 626-5938 or schedule a service appointment online at www.Turbohomeservices.com. Beat the summer heat with a perfectly operating, efficient air conditioner thanks to Turbo AC Repair’s experts!

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