Common Furnace Error Codes: Your Ultimate Guide

Do you hear that peculiar, continuous beep coming from your furnace? Notice something unusual in your furnace’s LED diagnostic light? Worry no more. This blog post will serve as your comprehensive guide to the most common furnace error codes.

Let’s start with a simple truth: understanding furnace error codes is crucial to maintain your comfort and safety at home. While it’s not a replacement for professional repair, knowing these codes can help you troubleshoot the problem, predict possible future issues, and communicate effectively with technicians.

Understanding Furnace Error Codes

A furnace error code is a specific message displayed on the furnace control board or through blinking LED lights. These messages are designed to help identify any issues your furnace may be experiencing.

Here are the most common error codes and their meanings:

1. Code 33 – Limit Circuit Fault

This code often implies that the furnace has exceeded its safe temperature limit. Overheating can lead to other components’ premature wear and tear, and it may even pose a fire risk. It’s advisable to turn off your furnace and contact a professional as soon as possible.

2. Code 13 – Limit Circuit Lockout

This error code indicates that your furnace has shut down after repeatedly exceeding its safe temperature limit. This issue could be caused by a variety of factors including blocked air filters, faulty limit switch, or poor ventilation.

3. Code 31 – Pressure Draft Safeguard

This code suggests issues with your furnace’s pressure switch. It could be triggered by anything from a blocked vent pipe to a broken pressure switch. Professional help is recommended for this issue.

4. Code 24 – Secondary Voltage Fuse is Open

This error code denotes that your furnace is having trouble with the transformer, possibly due to a power surge or wiring issue. Turn off your furnace and call a professional for an immediate inspection.

5. Code 41 – Blower Motor Fault

This error code implies a problem with the blower motor. The issue might be as simple as a loose wiring connection, or as severe as a completely burnt-out motor.

Simplified list of common furnace error codes for popular manufacturers

Various furnace manufacturers, including York, Carrier, Payne, Trane, Luxaire, Coleman, and Rheem. Here is a simplified list of common error codes. However, note that codes can vary widely by manufacturer and model, so it’s always best to consult your specific furnace’s manual or contact a professional HVAC technician if you’re encountering issues.

1. York Furnace Error Codes
   • Continuous amber/yellow: Flame sensing rod needs cleaning.
   • 1 amber/yellow flash: Thermostat signaling the need for cooling.
   • 2 amber/yellow flashes: Thermostat signaling the need for heat.
   • 4 amber/yellow flashes: Heating may be restricted due to airflow issues.
   • 5 amber/yellow flashes: Vent or combustion air system is restricted.
   • 1 red flash: Gas valve isn’t receiving power.
   • 2 red flashes: Pressure switch possibly stuck in ‘closed’ position.
   • 3 red flashes: Pressure switch stuck in ‘open’ position.
   • 4 red flashes: “High-limit” switch might be open.
   • 5 red flashes: Furnace’s roll-out switch or auxiliary switch may be open.
   • 6 red flashes: Modulating gas valve has failed.
   • 7 red flashes: Furnace is in “lock out mode”.
   • 1 green flash: Furnace performing successfully and no need for heating exists.
2. Trane Furnace Error Codes
   • Flashing slow: Normal, no call for heat.
   • Flashing fast: Normal, call for heat.
   • Continuous on: Replace control.
   • Continuous off: Check for power.
   • 2 flashes: System lockout (no flame) or reversed polarity.
   • 3 flashes: Pressure switch problem.
   • 4 flashes: Thermal (limit) protection off.
   • 5 flashes: Flame sensed with gas valve off.
3. Carrier Furnace Error Codes
   • 2 flashes: Pressure switch stuck open.
   • 3 flashes: Pressure switch stuck closed.
   • 4 flashes: Open temperature limit circuit.
   • 5 flashes: Shorted flame sensor.
   • 6 flashes: Polarity reversal.
   • 7 flashes: Gas valve circuit error.

Final Words

In summary, understanding furnace error codes is a proactive approach to home maintenance. Remember, these error codes serve as a warning sign that something is amiss. If you notice an error code on your furnace, don’t ignore it. Call a professional technician for a thorough inspection and necessary repairs.

Always remember – your safety should be your top priority. Some furnace issues might seem minor, but they can pose serious risks if left unchecked.

Do you have questions or experiences to share? Drop them in the comments section below, and let’s keep the conversation going.

Stay tuned for our next post where we delve into the world of HVAC maintenance tips!