Lennox Furnace Error Codes: Complete Diagnostic List
10 diagnostic codes documented · Official site ↗
🟡 Warning — Schedule Service
Ignition Failure
The error code 1 on your Lennox HVAC system indicates that the ignition system has failed to ignite the burner. This could be due to a few reasons, but it's important to note that attempting to fix this issue yourself can be dangerous and should be left to a professional technician. The ignition system is responsible for lighting the burner that heats the air in your home. If it's not working, your HVAC system won't be able to heat your home effectively.
Pressure Switch Stuck Closed
Error code 2 on your Lennox HVAC system indicates that the pressure switch is stuck closed. The pressure switch is a safety device that monitors the system's refrigerant pressure. When it's stuck closed, it can cause the system to over-pressurize, leading to potential damage and system lockout. This issue is common in Lennox systems due to dirt, debris, or faulty switch components.
Pressure Switch Stuck Open
Lennox error code 3 indicates that the pressure switch is stuck open. This switch is a safety component that monitors the system's pressure and prevents it from operating if there's a refrigerant leak. When it's stuck open, it's as if the system thinks there's a leak, even if there isn't. This can cause your system to lock out and not operate properly. This issue is typically caused by a faulty pressure switch or a problem with the system's pressure, such as a clogged filter or a refrigerant leak.
High Limit Switch Open
The Lennox 4 error, or High Limit Switch Open, indicates that your HVAC system has detected an abnormally high temperature and has shut down to prevent potential damage to the unit. This is a safety feature designed to protect your system and your home. The high limit switch is a safety device that monitors the temperature of the air leaving your furnace or air handler. If the temperature exceeds the set limit, the switch opens and shuts down the system.
Flame Rollout Switch Open
The Flame Rollout Switch Open error code (5) on your Lennox heating system indicates that the switch designed to prevent flame rollout is open, causing the system to shut down. This could be due to a faulty switch, improper gas pressure, or a problem with the ignition system. It's important to address this issue promptly to prevent potential safety hazards and damage to your system.
Pressure Switch System Lockout
The Lennox 6 error code indicates that the system's pressure switch has detected an abnormal pressure condition, causing the system to shut down. This could be due to a clogged filter, a refrigerant leak, or a faulty pressure switch. It's important to address this issue promptly to prevent further damage to your HVAC system.
Ignition Lockout
Lennox error code 7, or ignition lockout, means your heating system has temporarily shut down to prevent damage. This could be due to a safety feature kicking in, or a minor issue that needs addressing. Don't worry, it's not a gas leak or fire risk, but it's best to get it checked out.
Control Board Error
Error code 8 on your Lennox HVAC system indicates a problem with the control board. The control board is the brain of your system, managing all its operations. This error could be due to a faulty board itself or an issue with its wiring or components. It's important to address this issue promptly to prevent further damage or system failure.
Line Voltage Polarity Incorrect
The Lennox 9 error code indicates that the line voltage polarity in your HVAC system is incorrect. This means that the positive and negative wires are reversed, which can cause system malfunctions and potential damage to the components. It's important to have this issue resolved promptly to prevent further problems.
Lennox Code E250 - Indoor Blower Communication Error
Lennox error code E250 indicates a communication fault between the furnace control board and the indoor blower motor. Basically, the 'brains' of your furnace can't talk to the part that blows air through your vents. This usually means the furnace has shut down as a safety measure, since it can't properly regulate temperature without the blower working. This communication issue can stem from a few different things, like wiring problems, a faulty blower motor module, or even a problem with the control board itself. Because the blower is responsible for moving heated air throughout your home, this error will prevent your furnace from producing heat until the problem is resolved.