How to Check AC Compressor: A Comprehensive Guide

Figure 1: YORK air conditioner outside units.

The air conditioner compressor, also known as the AC compressor, is an essential component of your home's HVAC system. It is responsible for compressing refrigerant and sending it to the condenser for cooling. If your AC compressor fails, your HVAC system will not be able to cool your home effectively.

In this article, we'll show you how to check your AC compressor to ensure it's working correctly, including tools needed, steps to follow, and signs that your AC compressor needs checking. We'll cover the steps you need to take and provide tips to help you troubleshoot any problems you might encounter.

1. Why Check Your AC Compressor?

Checking your AC compressor is crucial because it ensures that your air conditioning system functions correctly. A faulty AC compressor can cause your air conditioning system to malfunction, leading to excessive energy consumption, higher electricity bills, and decreased comfort levels. Checking your AC compressor also helps you identify any potential problems before they become more severe.

2. 8 Steps to Check the AC Compressor

Tools Needed to Check the AC Compressor: gloves, screwdriver set, multimeter, clamp meter, refrigerant gauge, etc.

Here are some steps to follow when checking your AC compressor.

2.1 Step 1: Turn off Power

Before you start checking your AC compressor, make sure you turn off the power to your HVAC system. You can do this by shutting off the circuit breaker or pulling the fuse that powers your air conditioner.

Figure 2: Turn off the air conditioner.

2.2 Step 2: Access Your AC Compressor

Next, you need to access your AC compressor. Depending on the location of your HVAC system, your compressor may be outside your home or in a mechanical room inside your house. Once you locate your compressor, remove the cover to expose the unit.

2.3 Step 3: Inspect Your AC Compressor

Now that you have access to your AC compressor, it's time to inspect it. Look for signs of damage or wear and tear. Check the electrical connections, wiring, and the fan blades. Make sure everything looks intact and in good condition.

2.4 Step 4: Check the Voltage

To check the voltage, use a multimeter to test the electrical connections. Set your multimeter to the voltage setting and touch the probes to the terminals on the compressor. You should get a reading between 220 to 240 volts. If the voltage is too low or too high, it could indicate a problem with your compressor or your electrical system.

Figure 3: Multimeter.

2.5 Step 5: Check the Amperage

To check the amperage, you'll need to use a clamp meter. This device will measure the amount of electricity flowing through the compressor. Simply clamp the device around one of the power wires leading to the compressor and read the display. Your compressor should draw between 20 to 30 amps. If it's drawing too much or too little amperage, it could indicate a problem with your compressor.

2.6 Step 6: Check the Refrigerant Level

The refrigerant is what cools the air in your home. If your AC compressor is not producing enough cold air, there may be a problem with the refrigerant level.

To check the refrigerant level, you'll need a refrigerant gauge. Attach the gauge to the low-pressure port on the compressor and read the display. The pressure should be between 65 and 70 psi. If it's lower than that, you may need to recharge your system with more refrigerant.

2.7 Step 7: Listen for Unusual Sounds

As you're checking your AC compressor, listen for any unusual sounds. A grinding or squeaking noise could indicate a problem with the motor or fan blades. A hissing sound could indicate a refrigerant leak.

If you hear any strange noises, it's best to call a professional HVAC technician to diagnose and fix the issue.

2.8 Step 8: Check for Vibrations

Another thing to look out for when checking your AC compressor is vibrations. If your compressor is vibrating excessively, it could indicate a problem with the motor or the mounting brackets. Excessive vibration can also cause damage to other components in your HVAC system, so it's essential to address the issue as soon as possible.

Figure 4: The vibration of the air conditioner outdoor unit.

3. Signs That Your AC Compressor Needs Checking

After introducing the steps to check the AC compressor, let's next understand the signs that indicate that your air conditioner compressor needs checking. Here are some warning signs to keep an eye out for:

1.Poor Cooling Performance: If your air conditioner is blowing warm or hot air instead of cold air, it could be due to a malfunctioning AC compressor.

2.Loud or Unusual Noises: Strange noises like grinding, squealing, or banging sounds coming from your AC unit suggest that your AC compressor is not functioning correctly.

3.Vibration: Vibrations in the air conditioning system may occur due to a faulty compressor, which can cause damage to other components.

4.Leaks: If you notice any oily residue or leaks around your AC compressor, it may be caused by leaking refrigerant or oil, indicating a need for inspection.

5.Unpleasant Odors: If you smell unpleasant odors (like burning plastic or rubber), it could be due to a malfunctioning AC compressor.

6.High Electricity Bills: An inefficient AC compressor can consume more electricity, resulting in higher energy bills.

7.Short Cycling: It is a common issue when your AC turns on and off too frequently, which means that your compressor needs attention.

Figure 5: The structure of the air conditioner outdoor unit.

4. FAQs

4.1 How to Check If AC Compressor is Bad?

If your home AC system is not cooling properly or making unusual noises, it could be a sign that the compressor is bad. To check if the compressor is the problem, you can follow these steps:

1.Turn on the AC and listen for any clicking or buzzing sounds coming from the unit.
2.Check the pressure of the AC system using a gauge.
3.Look for signs of leakage around the AC compressor.
4.Check the electrical connections and ensure that the power supply to the unit is functioning properly.

If these checks don't reveal anything obvious, you may need to call a professional HVAC technician to perform a more thorough inspection and diagnose the issue with the compressor.

4.2 How Do I Test My AC Compressor?

Here are some steps to test your home AC compressor:

1.Turn off the power supply to the AC unit.
2.Locate the access panel on the outside of the unit.
3.Remove the access panel to expose the AC compressor.
4.Check for any visible damage or wear on the compressor, such as cracks or leaks.
5.Use a multimeter to check the electrical continuity of the compressor terminals. If the multimeter readings indicate no continuity, the compressor may be faulty and require replacement.

If you're unsure or uncomfortable with testing your AC compressor, it's recommended to hire a licensed HVAC technician to perform the inspection and any necessary repairs.

Figure 6: Test the air conditioning equipment.

4.3 How Do I Know If My AC Compressor is Low on Freon?

If your AC compressor is low on Freon, you may notice that the air coming from your vents is not as cold as it should be, or that it takes longer than usual to cool down your space.

Additionally, you may hear a hissing sound coming from the compressor or notice ice buildup on the refrigerant lines. It's always best to have a professional HVAC technician check for leaks and recharge the system if necessary.

4.4 How Do You Tell If a Compressor is Burnt out?

A burnt-out compressor in an air conditioning or refrigeration system may show signs such as inadequate cooling or heating, unusual noises, and high energy consumption. It may also trip the circuit breaker or cause the system to shut down altogether.

A trained technician can inspect the compressor and determine if it is burnt out by performing various tests and measurements on the unit.

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