How to Turn On AC Compressor

An AC compressor is the heart of your air conditioning system. If it’s not working, your AC won’t cool your home effectively. Whether you’re troubleshooting or simply trying to understand how to activate the compressor, this guide has you covered. Let’s explore step-by-step how to turn on an AC compressor, the common issues that prevent it from running, and actionable solutions to fix those problems.

AC Compressor Is Not Turning On (Quick Tips to Fix)

Before diving into specific reasons your AC compressor might not be turning on, here are a few quick steps to try:

1. Check the Power Supply: Ensure your AC unit is plugged in and receiving power.
2. Inspect the Thermostat Settings: Set your thermostat to "Cool" mode and lower the temperature.
3. Look for Tripped Circuit Breakers: Reset any tripped breakers connected to your AC.
4. Clean or Replace Filters: Dirty filters can obstruct airflow and prevent the compressor from working.

If these steps don’t solve the problem, one of the following reasons might be the culprit.

Common Reasons Why Your AC Compressor Won’t Turn On

1. Low Refrigerant Levels

Refrigerant is essential for cooling. If levels are too low, the pressure inside the system drops, preventing the compressor from activating.

What to Do:

• Call a professional to check for leaks and recharge the refrigerant.
• Regular maintenance can help avoid this issue.

2. Faulty Capacitor

The capacitor supplies the initial boost of energy your compressor needs to start. A faulty or blown capacitor can prevent the compressor from turning on.

Signs of a Faulty Capacitor:

• Humming sounds from the unit.
• AC starts but shuts off quickly.

What to Do:

• Replace the capacitor with the help of a certified technician.

3. Bad Relay or Contactor

The relay or contactor controls the electrical flow to your compressor. If they fail, your compressor won’t receive the power it needs.

What to Do:

• Have a professional inspect and replace faulty components.

4. Clogged Air Filter

Dirty air filters restrict airflow, which can overheat the system and prevent the compressor from running efficiently.

What to Do:

• Replace or clean the filters regularly—at least once a month during heavy AC use.

5. Faulty Thermostat

A malfunctioning thermostat may fail to signal the compressor to turn on.

What to Do:

• Check the batteries in your thermostat.
• Consider replacing the thermostat if it’s outdated or malfunctioning.

6. Condenser Coil Issues

Condenser coils release heat from the refrigerant. If they’re dirty or damaged, they can cause your compressor to overheat.

What to Do:

• Clean the condenser coils using a soft brush or hire a technician for deep cleaning.

7. Evaporator Coil Issues

Evaporator coils absorb heat from your home. If frozen or dirty, they can disrupt the entire cooling cycle.

What to Do:

• Turn off the AC and allow the coils to thaw.
• Check for underlying issues like restricted airflow or low refrigerant.

8. Dirty or Damaged Compressor

The compressor itself can become dirty or damaged over time, leading to inefficiencies or failure.

What to Do:

• Clean the compressor housing and ensure there are no visible signs of damage.
• Consult a technician if you suspect internal issues.

9. Incorrect Installation

Improper installation can lead to electrical or mechanical issues, affecting the compressor’s performance.

What to Do:

• Ensure your AC unit is installed by licensed professionals like EMGAir.
• If installation issues are suspected, schedule an inspection.

10. Old Age

AC compressors typically last 10-15 years. If yours is older, wear and tear might be the issue.

What to Do:

• Consider replacing the compressor or upgrading to a new AC unit.
• Regular maintenance can extend the lifespan of your system.

11. Electrical Problems

Loose wires, blown fuses, or other electrical issues can prevent your compressor from starting.

What to Do:

• Inspect visible wires for damage.
• Always consult a licensed electrician or HVAC technician to handle electrical issues safely.

How Do I Know My AC Compressor Has A Serious Issue?

Winding Problems In The Electric Motor

The compressor motor relies on windings to function. Damage to these windings can cause serious operational issues.

What to Do:

• Have a professional measure the windings with a multimeter to detect faults.

Open Windings

An open winding occurs when the circuit is broken, disrupting the motor’s operation.

What to Do:

• Replace or repair the motor as needed.

Grounded Windings

This happens when a winding contacts the compressor casing, causing electrical shorts.

What to Do:

• Disconnect power and consult a technician immediately.

Shorted Windings

Short circuits within the windings can damage the compressor motor.

What to Do:

• Replace the compressor motor if shorted windings are confirmed.

Compressor Is Stuck Or Locked Up

A locked compressor can’t pump refrigerant, which halts the cooling process.

What to Do:

• Try a hard start kit to provide an extra boost to the motor.
• If that fails, replacement may be necessary.

AC Compressor Costs

Replacing an AC compressor can cost between $800 and $2,800, depending on the make, model, and labor fees. Regular maintenance and prompt repairs can help minimize these costs.

Preventative Maintenance & Care

To ensure your AC compressor lasts longer and works efficiently:

• Schedule annual professional inspections.
• Clean or replace air filters regularly.
• Keep the outdoor unit free of debris.
• Monitor refrigerant levels and address leaks immediately.

FAQs

What Is An AC Compressor?

The AC compressor is a vital component that circulates refrigerant through the system, enabling it to absorb and release heat.

How Long Does An AC Compressor Last?

Typically, an AC compressor lasts 10-15 years with proper maintenance.

How Can I Tell If My AC Compressor Is Not Turning On?

Look for these signs:

• No cool air from vents.
• Clicking or humming noises from the outdoor unit.
• The fan runs, but the compressor doesn’t engage.

Why Is My AC Compressor Not Turning On Capacitor?

A failed capacitor is one of the most common reasons for a non-functioning compressor. It may make a humming sound but fail to start. Replacing the capacitor can usually resolve this issue.

FAQs About EMGAir

Why Choose EMGAir for Your AC Needs?

EMGAir is dedicated to providing professional, reliable, and affordable HVAC services. From installation to repair, we’re your trusted partner in comfort.

Does EMGAir Offer Emergency Services?

Yes, EMGAir provides 24/7 emergency AC repair services to ensure your home stays comfortable.

How Can I Schedule a Service with EMGAir?

Scheduling is simple! Contact us through our website or call our customer support team to book an appointment.

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