Troubleshooting Your Goodman Furnace Without Error Codes (2024)

When there’s a problem with your Goodman furnace, you can check the code displayed and take appropriate action. But if your furnace isn’t working yet, there are no codes, what should you do?

Your Goodman furnace isn’t working and not displaying codes because there’s a problem with the gas valve, flue line, circuit board, or power supply. Fix the furnace by ensuring it’s getting sufficient gas, the flue line is clean, and there are no issues with the power supply and circuit board.

This article helps you identify why your Goodman furnace isn’t working and why it’s not showing any error codes. I’ll explain how to fix each issue to ensure your home stays warm throughout winter.

Closed Gas Valve

There are numerous reasons for a Goodman furnace to stop working and not show any error codes. Always start with simple causes that are easy to fix. Don’t waste your time, effort, and money trying to diagnose and replace something that isn’t even broken.

So, start with the gas valve. The gas valve is located on the gas supply line. It’s a relatively small device that opens up once the furnace is ready for ignition. Once the gas valve is open, gas can be pushed into the furnace. This allows a flame to be created when the ignitor or pilot light performs its specific function.

When the gas valve is closed, gas won’t flow to the burners. This means ignition won’t be possible. This issue can lead to a non-working HVAC system in some Goodman furnaces, yet no error codes will be displayed.

How To Fix

First, check the thermostat to see if there’s a red LED light. The light should be solid, not flickering. This indicates power is getting to the device, but it doesn’t work from that point on.

You’ll need to get inside the furnace to check the gas valve. Here’s what you need to do:

1. Turn off the power to the furnace at the circuit breaker.
2. Open the furnace up by removing the front panel.
3. Locate the gas valve. Check for the gas supply line — you’ll find the valve attached to this pipe.
4. There should be a small switch on the gas valve. If the switch is closed, open it.

The video below will guide you through the process of checking the gas valve:

Blocked Flue Line

The combustion chamber in your Goodman furnace plays a crucial role in ensuring gas emissions are pushed out of the system instead of your home. A flue line is connected to the combustion chamber.

As combustion gases are produced, they are pushed into the flue line. The combustion blower ensures the gases only enter the flue line.

Since you’re not getting any codes on your Goodman furnace, that’s a sign that something is blocking the flue line. If the flue line is blocked, gases can’t exit the furnace. This will cause the furnace to stop working, but some models won’t show an error code.

How To Fix

If the flue line is blocked, you need to clean it to restore functionality. The first step is to determine whether this is causing your Goodman furnace to stop working. Here’s how to diagnose it:

1. Locate the flue line and take a close look. Make sure to check the area where gases are expelled out of your house too. Some homes have a line that runs into the chimney. Other homes use a direct outlet instead.
2. If something’s blocking the flue line, remove it. If you cannot find anything at the outlet, check the flue line itself.

Once you’ve removed the blockage, your furnace should start working again.

The video below gives you a guide on how you can determine if your flue line is blocked:

Damaged Circuit Board

There are a few boards inside the furnace, but the mainboard is the most important one. It’s sometimes referred to as the furnace circuit board. The board connects to different parts of the furnace, including:

• Thermostat
• Ignitor
• Burners
• Combustion chamber
• Blower assembly

When the circuit board is damaged, a few different problems can pop up. You might find that the thermostat is dead or doesn’t send a signal to the burner when you change the temperature. It’s also possible that some parts of the furnace fail to initiate. A damaged circuit board can’t display error codes when the furnace runs into an issue.

How To Fix

Replace the circuit board to fix this issue. But you first want to make sure that the circuit board is causing the problems, not something else. This can be a fairly expensive fix, but it’s better than trying to repair a fried board, as it can cause you to run into issues in the future.

Here’s what you have to do:

1. Open up your furnace.
2. Locate the main circuit board.
3. If necessary, remove the circuit board for a close inspection. However, you can start with a multimeter before removing the board.
4. Check to see if power is going to the circuit board. Also, use the multimeter to determine if the board can output any electrical signals.
5. Perform a visual inspection. Look for signs of damage, such as burn marks caused by a power surge.
6. If you find damaged parts or problems with power distribution, get a replacement board.

Check the video below to learn how to replace a furnace control board:

Power Supply Issues

Every part of the furnace requires a constant supply of power to operate normally. If there are problems with the power supply, your Goodman furnace can’t operate normally.

For example, an unpowered thermostat means you can’t manage and monitor the furnace. No power also means no error codes.

How To Fix

You need to test all electrical components of your furnace to determine if there’s an issue with the power supply. Start at the source of power and work your way from there. Check all connections.

Try to identify what parts of the furnace aren’t turning on.

You can inspect those parts more closely, making it easier to find the problem area.

Summary

It’s easy to fix a Goodman furnace that isn’t working and displaying error codes. The most common problems are a closed gas valve and a blocked flue line. They’re relatively easy to fix without the need for a professional.

However, sometimes the issue is more extensive and requires a replacement part or advanced skills and know-how.

If you’re having any other problems with your Goodman furnace, I recommend reading through our Complete Goodman Furnace Troubleshooting Guide.