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American Standard Furnace Codes

How to Troubleshoot American Standard Furnace Codes

Wondering what to do if your American Standard furnace displays an error code? American Standard furnaces are known for their durability and efficiency, but sometimes they can encounter problems that…

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Wondering what to do if your American Standard furnace displays an error code?

American Standard furnaces are known for their durability and efficiency, but sometimes they can encounter problems that affect their performance. One way to troubleshoot your American Standard furnace is to check the error codes that are displayed on the control board. These codes can help you identify the source of the issue and take the appropriate steps to fix it.

In this blog post, we will explain what some of the most common American Standard furnace codes mean and how to fix them.

What are American Standard Furnace Codes?

American Standard furnace codes are alphanumeric codes that show on the LED display of the control board. The control board is usually located inside the furnace cabinet or on the blower compartment door. 

The codes can be green, amber, or red, and they flash in a series of intervals to signal normal operation or system issues.

For example, a two-flash code will flash on and off twice, stay off for two seconds, then repeat. A rapid flash is only used during factory testing and indicates an error.

How to Read American Standard Furnace Codes?

To read American Standard furnace codes, you need to check the color and the number of flashes of the LED display. Each color and number combination has a different meaning and indicates a different issue. Here is a summary of what each color and number means:

  • Green flashes: Normal operation
    • One green flash: No call for heat
    • Two green flashes: No error codes stored in memory
    • Three green flashes: No error codes stored in memory
    • Rapid green flash: Factory testing mode
  • Amber flashes: Normal operation with call for heat or cooling
    • One amber flash: Call for cooling
    • Two amber flashes: Call for heat
    • Three amber flashes: Temperature fulfilled, burner ending cycle
    • Four amber flashes: Restriction in circulating air system
    • Five amber flashes: Restriction in vent or combustion air system
    • Rapid amber flash: Possible low flame
  • Red flashes: Error or fault
    • One red flash: Flame present with no gas valve power
    • Two red flash: Pressure switch stuck closed
    • Three red flash: Pressure switch stuck open
    • Four red flash: 24-volt fuse or high-limit switch open

How to Fix American Standard Furnace Codes?

Depending on the type and severity of the code, you may be able to fix it yourself or need to contact a professional technician. Here are some possible solutions for each code:

One red flash: Flame present with no gas valve power

This code indicates that there is a gas leak or a slow gas valve closure. This can be dangerous and should be fixed as soon as possible.

  • The most likely cause of this problem is a faulty gas valve that is either leaking gas to the burner or closing too slowly. You should replace the gas valve as soon as possible.
  • Another possible cause is a low gas pressure that prevents the gas valve from opening or closing properly. You should check the gas pressure and make sure it is within the recommended range. If it is too low or too high, you should adjust it accordingly.
  • A third possible cause is a defective ignition control module that is not sending power to the gas valve when needed. You should test the ignition control module and make sure it is working properly. If it is faulty, you should replace it with a new one.

Two red flash: Pressure switch stuck closed

This code indicates that the pressure switch is not opening when it should. This can prevent the furnace from starting or running properly.

  • One possible cause of this problem is an incorrect pressure switch wiring that prevents the switch from opening or closing correctly. You should check the wiring of the pressure switch and make sure it is connected correctly. If there are any loose or broken wires, you should fix them or replace them.
  • Another possible cause is a faulty pressure switch that does not respond to changes in pressure. You should replace the pressure switch with a new one and make sure it is compatible with your furnace model.
  • A third possible cause is a malfunctioning inducer motor that does not create enough suction to close the pressure switch. You should test the inducer motor and make sure it is working properly. If it is not spinning or making noise, you should replace it with a new one.

Three red flash: Pressure switch stuck open

This code indicates that the pressure switch is not closing when it should. This can prevent the furnace from igniting or staying lit.

  • One possible cause of this problem is a blocked vent pipe or air intake pipe that reduces the airflow and prevents the pressure switch from closing. You should clear any obstructions in the pipes using a vacuum cleaner or a brush. You should also check for any cracks or holes in the pipes and seal them if necessary.
  • Another possible cause is a cracked or clogged pressure switch hose that prevents the pressure switch from sensing the pressure changes. You should replace the pressure switch hose if it is damaged or dirty. You should also make sure it is securely attached to the pressure switch and the inducer motor.
  • A third possible cause is a faulty combustion air blower that does not provide enough air for combustion and prevents the pressure switch from closing. You should test the combustion air blower and make sure it is working properly. If it is not blowing air or making noise, you should replace it with a new one. Watch here how to replace the air blower motor.

Four red flash: 24-volt fuse or high-limit switch open

This code indicates that there is an electrical problem or an overheating issue. This can damage your furnace components or cause a fire hazard.

  • One possible cause of this problem is an improperly sized ducting system that does not match your furnace capacity. If your ducts are too small or too large, they can affect the airflow and cause overheating or underheating. You should check and correct the size of your ducting system and make sure it matches your furnace capacity.
  • Another possible cause is a dirty or clogged air filter that reduces the airflow and causes overheating or underheating. You should replace your air filter every 1–3 months depending on usage and environment. A dirty air filter can also affect the indoor air quality and cause health problems.
  • A third possible cause is a faulty blower motor that does not circulate the air properly and causes overheating or underheating. You should test your blower motor and make sure it is working properly. If it is not spinning or making noise, you should replace it with a new one.
  • A fourth possible cause is an open fuse on the control board that cuts off the power supply to the furnace. You should replace the fuse on the control board if it is blown or open. You should also make sure you use the correct fuse size and type for your furnace model.
  • A fifth possible cause is a restricted circulating airflow that prevents the heat from being transferred properly and causes overheating or underheating. You should clear any obstructions in the airflow using a vacuum cleaner or a brush. You should also check for any leaks or gaps in the ducts and seal them if necessary.

Conclusion

American Standard furnace codes are useful tools to troubleshoot your furnace and keep it running smoothly. However, if you are not comfortable or confident in performing any of the repairs yourself, you should always contact a professional technician for assistance. 

Remember to follow all safety precautions and turn off the power supply before working on your furnace.

We hope this blog post has helped you understand how to troubleshoot American Standard furnace codes. Read here more posts.

I'm an HVAC enthusiast and a passionate writer dedicated to sharing valuable insights and practical tips about heating, cooling, ventilation, and air conditioning systems.

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Hi there, I'm Robert Brooks

Hi there, I'm Robert Brooks

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