How Do I Know My Goodman Limit Switch Has Problem?

A Goodman limit switch is a safety device that is installed in a Goodman furnace to protect against overheating. It is designed to cut off power to the furnace if the temperature inside the furnace exceeds a certain level.

The limit switch is an important component of the furnace, as it helps to ensure the safety of the appliance and the people using it. However, like any mechanical device, the limit switch can sometimes fail or malfunction, leading to problems with the operation of the furnace.

If you are experiencing issues with your Goodman furnace, a faulty limit switch may be the cause. In this article, we will discuss common Goodman limit switch problems, their causes, and how to troubleshoot and fix them.

Common Problems

One of the most common problems associated with Goodman limit switches is the 4-blink error code. This error code is displayed when the furnace’s diagnostic light flashes 4 times in a row, indicating an issue with the limit switch.

This problem can be caused by a variety of factors, including an open main limit switch or an open auxiliary limit switch. Other common problems with Goodman limit switches include the furnace shutting off unexpectedly, the furnace not starting at all, or the furnace running erratically.

If you are experiencing any of these issues with your Goodman furnace, it is important to diagnose and fix the problem as soon as possible to ensure the safety and reliability of the appliance.

Causes of Goodman Limit Switch Problems

There are several common causes of Goodman limit switch problems, including:

1. Dirty or clogged air filters: When the air filter becomes dirty or clogged, it can restrict the flow of air through the furnace, causing the furnace to overheat and trip the limit switch.
2. Blocked or restricted vent pipes: If the vent pipes that carry exhaust gases out of the furnace are blocked or restricted, it can cause the furnace to overheat and trip the limit switch.
3. Obstructed return air ducts: If the return air ducts that bring air into the furnace are obstructed, it can cause the furnace to overheat and trip the limit switch.
4. Dirty or clogged a/c evaporator coils: If your furnace is equipped with an a/c evaporator coil, and it becomes dirty or clogged, it can restrict the flow of air through the furnace and cause the furnace to overheat and trip the limit switch.

It is important to regularly maintain your furnace to prevent these issues from occurring. This includes changing the air filter regularly, checking the vent pipes and return air ducts for blockages, and cleaning the a/c evaporator coil if necessary. By keeping your furnace well-maintained, you can help prevent problems with the limit switch and ensure that your furnace is running safely and efficiently.

Steps for Troubleshooting and Fixing

If you are experiencing problems with your Goodman furnace, there are several steps you can take to troubleshoot and fix the issue. These steps include:

Check the Auxiliary Limit Switch

If you are experiencing a 4-blink error code, it could be caused by an open main limit switch or an open auxiliary limit switch. To check the auxiliary limit switch, you will need to locate it (it is usually mounted on the side of the blower) and test it with a voltage meter. If the auxiliary limit switch is faulty, it will need to be replaced.

Test the Blower Motor

The blower motor is responsible for circulating air through the furnace and into your home. If the blower motor is faulty, it can cause problems with the operation of the furnace. To test the blower motor, you will need to disconnect the power to the furnace and then remove the blower motor.

With the power still off, you can test the blower motor by connecting a voltage meter to the leads of the motor and then turning on the power. If the voltage reading is normal, the motor is likely working properly.

If the reading is low, the motor may be faulty and will need to be replaced.

Test the Blower Motor Capacitor

The blower motor capacitor is a small electrical device that helps start the blower motor and keep it running. If the capacitor is faulty, it can cause the blower motor to run erratically or not at all.

To test the blower motor capacitor, you will need to disconnect the power to the furnace and then locate the capacitor, which is usually located near the blower motor. You can test the capacitor with a capacitor tester or by using a voltage meter.

If the capacitor is faulty, it will need to be replaced.

Clean the a/c Evaporator Coil

If your furnace is equipped with an a/c evaporator coil, and it becomes dirty or clogged, it can restrict the flow of air through the furnace and cause the furnace to overheat and trip the limit switch.

To clean the a/c evaporator coil, you will need to turn off the power to the furnace and then remove the panel that covers the coil. Using a soft brush or vacuum, gently clean the coil to remove any dirt or debris.

Be sure to follow the manufacturer’s instructions and take all necessary safety precautions when cleaning the a/c evaporator coil.

If you are still having issues with your Goodman furnace after attempting these troubleshooting steps, it is recommended to consult a heating and cooling professional for further assistance.

How to Fix Goodman Limit Switch?

Here are some additional tips for preventing Goodman limit switch problems:

Keep the Furnace Area Clean and Clear

Make sure to keep the area around your furnace clean and free of clutter. This will help ensure that there is enough air circulation around the furnace and reduce the risk of overheating and tripping the limit switch.

Check the Furnace’s Thermostat Settings

If the thermostat is set too high, it can cause the furnace to overheat and trip the limit switch. Make sure to check the thermostat settings and set it to a comfortable temperature.

Check for Drafts

If your furnace is located near a drafty door or window, it can cause the furnace to overheat and trip the limit switch. To prevent this, make sure to seal any drafts around your home to help maintain a consistent temperature.

Check for Gas Leaks

If there is a gas leak in your home, it can cause the furnace to overheat and trip the limit switch. If you suspect a gas leak, immediately turn off the gas supply and call a professional to fix the issue.

Use a Programmable Thermostat

A programmable thermostat can help you save energy and money by allowing you to set the temperature to automatically turn up or down at certain times of the day. This can help prevent overuse of the furnace and reduce the risk of overheating and tripping the limit switch.

By following these tips, you can help prevent Goodman limit switch problems and ensure that your furnace is running safely and efficiently.

Tips for Preventing Future Goodman Limit Switch Problems

To prevent future Goodman limit switch problems, it is important to regularly maintain your furnace. Some tips for preventing issues with the limit switch include:

Regularly Change the Air Filter

One of the most common causes of limit switch problems is a dirty or clogged air filter. To prevent this issue, it is important to regularly change the air filter according to the manufacturer’s recommendations. This will help ensure that the furnace is receiving a consistent flow of clean air and reduce the risk of overheating and tripping the limit switch.

Maintain the Furnace Regularly

It is important to perform regular maintenance on your Goodman furnace to ensure that it is running safely and efficiently. This includes checking and cleaning the vent pipes and return air ducts, as well as cleaning the a/c evaporator coil if necessary. By performing regular maintenance, you can help prevent problems with the limit switch and extend the lifespan of your furnace.

Consult a Heating and Cooling Professional

If you are unsure of how to perform maintenance on your Goodman furnace or are having persistent issues with the limit switch, it is recommended to consult a heating and cooling professional. They will be able to diagnose and fix any issues with your furnace and provide recommendations for preventing future problems.

By following these tips, you can help prevent future Goodman limit switch problems and ensure that your furnace is running safely and efficiently.

Editor’s Note

It’s possible that the blower motor or the blower motor capacitor could be causing the issue with your furnace. The blower motor is responsible for circulating air through the furnace and into your home, and if it is faulty, it could cause the furnace to operate improperly. The blower motor capacitor is a small electrical device that helps start the blower motor and keep it running, and if it is faulty, it could cause the blower motor to run erratically or not at all.

If you have checked the air filter, vent pipe, and a/c coil, and have not found any issues, it might be worth checking the blower motor and capacitor. You can test the blower motor by disconnecting the power to the furnace and then removing the blower motor from the furnace.

With the power still off, you can test the blower motor by connecting a voltage meter to the leads of the motor and then turning on the power. If the voltage reading is normal, the motor is likely working properly.

If the reading is low, the motor may be faulty and will need to be replaced.

To test the blower motor capacitor, you will need to disconnect the power to the furnace and then locate the capacitor, which is usually located near the blower motor. You can test the capacitor with a capacitor tester or by using a voltage meter. If the capacitor is faulty, it will need to be replaced.

I hope this helps. If you are still having issues with your furnace after checking these potential causes, it might be worth consulting a heating and cooling professional for further assistance.

Conclusion

Goodman limit switch problems can be caused by a variety of factors, including dirty or clogged air filters, blocked or restricted vent pipes, obstructed return air ducts, and dirty or clogged a/c evaporator coils. You might also try to downflow the furnace.

By following the steps for troubleshooting and fixing these issues, you can help ensure that your Goodman furnace is running safely and efficiently. However, if you are still experiencing problems with your furnace after attempting to fix the issue on your own, it is recommended to consult a heating and cooling professional for further assistance.

A professional will be able to diagnose and fix any issues with your furnace and provide recommendations for preventing future problems. By consulting a professional, you can have peace of mind knowing that your furnace is in good hands and that it is operating safely and reliably.