What to Do When Your Air Conditioner Compressor Is Not Turning On

HVAC Service systems Professionals
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If the fan and blower fan is running, but the compressor won’t activate, a technician should initially examine for blown or tripped fuses in the disconnect block. A blown-out fuse or tripped breaker shouldn’t be expected or occur frequently.

Solving any problem AC can be straightforward with professional guidance or assistance. If you need help with any aspect of your AC unit, you can visit this site to book an inspection with some of Arionza’s top HVAC contractors.

Check the Power

Check the Power - air conditioning compressor doesn't start
Source: homeairguides.com

Whenever your air conditioning compressor doesn’t start up correctly, the first thing to check is its electricity source. If this is indeed the case, perhaps a blown fuse or circuit breaker needs replacing, or something similar could be the culprit.

Air conditioners with outdoor units connect to an interior system switch similar to light switches for power, which regulates how electricity flows to these components and ensures your AC doesn’t switch on when switched off. If it is switched off, your air conditioning won’t turn on at all!

Other issues that could keep an AC compressor from turning on include a malfunctioning thermostat that doesn’t know the desired temperature, dirty filters, or an inoperable compressor motor.

Air conditioning compressor motors are typically hermetically sealed so repairing them requires professional help; however, capacitors and starter relays are typically easy to replace, providing relief quickly. A humming sound may indicate an AC compressor is trying to access power from a non-functioning capacitor; returning this may help fix this problem.

Check the Thermostat

Check the Thermostat for ac
Source: aireserv.com

If your thermostat is set to cool, but the compressor isn’t activating, there may be another cause. Check your circuit breaker to ensure the one for air conditioners hasn’t been tripped by overly multiple appliances being used at once or due to power surges after big storms; reset this switch in your service panel, turn it off and back on.

Check your indoor air handler unit’s system switch, which looks similar to a light switch, regularly; if this is switched off, any power to the compressor could be lost, leading to sudden shutdowns of service.

Finally, your compressor may not be functioning due to a refrigerant leak which will need to be professionally diagnosed and fixed by a trained service provider. A start capacitor stores potentially dangerous voltages that could fail if damaged or overheated, thus necessitating professional inspection and repair as soon as possible.

Check the Fan

checking hvac Fan

A fan found in an outdoor unit assists with providing cool air to the compressor to prevent overheating, keeping it running optimally and thus prolonging its life. If this fan stops functioning, overheating may occur, which will eventually shut it off automatically.

To maintain the optimal functioning of your air conditioning system, inspect its fan for any signs of trouble, such as broken wiring or disjointed power connections, and fix them immediately if any arise.

If the problem continues, it is wise to call in a professional for further examination of your air conditioner. They will inspect for any worn parts or components that need replacement as well as test for potential issues that could prevent its operation from starting up properly.

If your compressor still refuses to start, a start capacitor replacement could be in order. As this component stores highly sensitive high-voltage parts, professional services may be necessary in order to access and install one successfully.

Check the Condenser

If the fan is running, but the compressor motor won’t start up, there may be an electrical problem. Check for tripped circuit breakers or blown fuses; regular trips could indicate voltage or current fluctuations that cause overheating that shut off the compressor motor.

Safety features built into the system ensure the greatest protection. Two pressure switches detect too low or too high a pressure and automatically shut off the compressor if they detect too little or too much airflow.

Maintaining an effective air conditioner requires routinely maintaining both filters and condenser coils for optimal operation, as well as clearing away any obstructions such as vines, plants, or debris that obstruct its functioning and prevent proper airflow.

Without professional assistance available to you, cleaning coils is best achieved by taking this DIY route – remove the cover, then use refrigerator coil brush or soft vacuum attachments to scrub away dirt build-up using refrigerator coil brush / soft brush attachment and soft vacuum attachment with soft bristle head if applicable, then rinse with a hose if desired.

Maintaining Airflow: Checking the Air Filter

Checking if the Air Filter is dirty
Source: metropolitanairconditioning.com.au

The first step in troubleshooting an air conditioning system is to inspect the air filter. A clogged or dirty air filter can significantly impede airflow, causing unnecessary strain on the air conditioning system.

By replacing a dirty filter with a clean one, you can ensure proper airflow, improve the performance of the compressor, and enhance the energy efficiency of the entire system. Regularly checking and replacing the air filter can prevent many common issues and extend the lifespan of your air conditioner.

Wiring Woes: Inspecting the Electrical Connections

Faulty or damaged wiring can disrupt the electrical connection to the compressor, causing the air conditioner to malfunction. Carefully examine the wiring connections, looking for any signs of wear, fraying, or loose connections.

If you discover any issues, it’s best to consult a professional HVAC technician to address and repair the wiring problems. Attempting to fix electrical issues without the proper expertise can be dangerous and may lead to more significant problems.

Calling in the Pros: When to Seek Professional HVAC Service

Professional HVAC Service
Source: cardinalplumbingva.com

If the troubleshooting steps mentioned above and the additional tips haven’t resolved the issue, it’s time to call a licensed HVAC technician. HVAC professionals have the expertise and specialized tools to diagnose and repair complex problems with the compressor, electrical components, or refrigerant levels.

Their knowledge and experience ensure a safe and effective resolution to the problem, preventing further damage to the system and ensuring your air conditioner is back up and running as quickly as possible.


While common troubleshooting steps for an air conditioner compressor not turning on are essential, paying attention to additional points can help pinpoint the issue more accurately. Remember, when in doubt or if the problem persists, it’s always best to consult a qualified HVAC technician for expert assistance.