HVAC Systems Error Codes
Decode error codes on air conditioners, furnaces, heat pumps, and thermostats from all major HVAC brands.
HVAC systems — including air conditioners, furnaces, heat pumps, and mini-split systems — use error codes to communicate issues with their operation. These codes often appear as blinking LED sequences on the control board or alphanumeric codes on the thermostat display. Understanding these codes is important for maintaining comfort and safety in your home. This section provides detailed explanations for HVAC error codes across major brands, including what each code indicates, common causes, safe troubleshooting steps, and clear guidance on when to contact a licensed HVAC technician.
Common Brands
Common Error Code Formats
E1CH34F1P1H6U4L3Error Code Guides (52)
Apple TV Flashing Light – Meaning, Causes & Fix
Apple · Streaming Player · Flashing Light
Netgear Router Power Light Amber – Meaning, Causes & Fix
Netgear · Router · Power Light Amber
TP-Link Internet Light Off – Meaning, Causes & Fix
TP-Link · Router · Internet Light Off
Hisense TV Blue Light On But No Picture – Meaning, Causes & Fix
Hisense · Smart TV · Blue Light No Picture
Fire TV Storage Critically Low Message – Meaning, Causes & Fix
Amazon · Streaming Player · Storage Critically Low
Sony TV Amber Light Blinking – Meaning, Causes & Fix
Sony · Smart TV · Amber Light Blinking
Sony TV Green Light Flashing – Meaning, Causes & Fix
Sony · Smart TV · Green Light Flashing
Roku Remote Flashing Green Light – Meaning, Causes & Fix
Roku · Streaming Player · Remote Flashing Green
TCL TV Stuck On Logo – Meaning, Causes & Fix
TCL · Smart TV · Stuck On Logo
Samsung TV Red Standby Light Blinking – Meaning, Causes & Fix
Samsung · Smart TV · Red Standby Light Blinking
Samsung TV Update Failed Message – Meaning, Causes & Fix
Samsung · Smart TV · Update Failed
LG TV HDMI No Signal – Meaning, Causes & Fix
LG · Smart TV · HDMI No Signal
LG TV Memory Full Message – Meaning, Causes & Fix
LG · Smart TV · Memory Full
Roku Low Power Warning – Meaning, Causes & Fix
Roku · Streaming Player · Low Power
Daikin Air Conditioner Flashing Timer Light – Meaning, Causes & Fix
Daikin · Air Conditioner · Flashing Timer Light
Bryant Furnace Limit Circuit Lockout – Meaning, Causes & Fix
Bryant · Furnace · Limit Circuit Lockout
Daikin Indoor Unit Green Light Flashing – Meaning, Causes & Fix
Daikin · Mini Split · Green Light Flashing
American Standard Thermostat Offline – Meaning, Causes & Fix
American Standard · Thermostat · Offline
Mitsubishi Mini Split Timer Light Flashing – Meaning, Causes & Fix
Mitsubishi · Mini Split · Timer Light Flashing
Goodman Furnace 4 Flashing Lights – Meaning, Causes & Fix
Goodman · Furnace · 4 Flashing Lights
Rheem Furnace Pressure Switch Error – Meaning, Causes & Fix
Rheem · Furnace · Pressure Switch Error
Rheem Water Heater Vacation Mode – Meaning, Causes & Fix
Rheem · Water Heater · Vacation Mode
York Furnace Pressure Switch Stuck Open – Meaning, Causes & Fix
York · Furnace · Pressure Switch Stuck Open
Mitsubishi Mini Split Green Light Blinking – Meaning, Causes & Fix
Mitsubishi · Mini Split · Green Light Blinking
Carrier Furnace Pressure Switch Open – Meaning, Causes & Fix
Carrier · Furnace · Pressure Switch Open
Carrier Thermostat Offline – Meaning, Causes & Fix
Carrier · Thermostat · Offline
Lennox Thermostat WiFi Offline – Causes & Fix
Lennox · Thermostat · WiFi Offline
Trane Thermostat Waiting Message – Meaning, Causes & Fix
Trane · Thermostat · Waiting
Goodman Furnace Open Limit Switch – Meaning, Causes & Fix
Goodman · Furnace · Open Limit Switch
Bryant Furnace Error Code 33 – Meaning, Causes & Fix
Bryant · Furnace · 33
American Standard Furnace Error Code 184 – Meaning, Causes & Fix
American Standard · Furnace · 184
York Furnace Red Light Flashing 4 Times – Meaning, Causes & Fix
York · Furnace · 4 Flash
Daikin Error Code A3 – Meaning, Causes & Fix
Daikin · Mini Split · A3
Rheem Furnace Error Code 57 – Meaning, Causes & Fix
Rheem · Furnace · 57
Mitsubishi Mini Split P6 Error Code – Meaning, Causes & Fix
Mitsubishi · Mini Split · P6
Lennox Furnace Error Code 201 – Meaning, Causes & Fix
Lennox · Furnace · 201
Trane Furnace 3 Flashing Red Lights – Meaning, Causes & Fix
Trane · Furnace · 3 Flash
Goodman Furnace Pressure Switch Stuck Open – Meaning, Causes & Fix
Goodman · Furnace · Pressure Switch Stuck Open
Carrier Furnace Error Code 31 – Meaning, Causes & Fix
Carrier · Furnace · 31
Daikin Error Code U4 Explained – Meaning, Causes & Fixes
Daikin · Air Conditioner / Mini Split · U4
Goodman Furnace 3 Blinking Red Lights – Meaning, Causes & Fixes
Goodman · Gas Furnace · 3 Blinks
Rheem Furnace 7 Flashing Lights Error – Meaning, Causes & Fixes
Rheem · Gas Furnace · 7 Flashes
York AC Error Code 11 Explained – Meaning, Causes & Fixes
York · Air Conditioner / Heat Pump · 11
Mitsubishi Mini Split P8 Error Code Explained – Meaning, Causes & Fixes
Mitsubishi · Mini Split / Heat Pump · P8
Lennox AC Error Code 292 – Meaning, Causes & Fixes
Lennox · Air Conditioner / Heat Pump · 292
Trane Error Code 79 Explained – Meaning, Causes & Fixes
Trane · Air Conditioner / Heat Pump · 79
Carrier AC Error Code 13 – Meaning, Causes & Fixes
Carrier · Air Conditioner / Furnace · 13
Trane Error Code 126 Explained – Meaning, Causes & Fixes
Trane · Furnace · 126
Carrier AC Error Code 33 – Meaning, Causes & Fixes
Carrier · Air Conditioner / Furnace · 33
Lennox AC Error Code 413 – Meaning, Causes & Fixes
Lennox · Air Conditioner · 413
Mitsubishi Mini Split U4 Error Code – Meaning, Causes & Fixes
Mitsubishi · Mini Split · U4
Daikin Error Code U0 Explained – Meaning, Causes & Fixes
Daikin · Air Conditioner / Mini Split · U0
Frequently Asked Questions
Is it safe to keep running my HVAC system when it shows an error?
It depends on the error. Some codes indicate minor sensor issues that don't affect safety, while others signal serious problems like overheating or refrigerant leaks. Check the specific error guide before continuing operation.
How do I read blinking LED error codes on my furnace?
Most furnaces have a diagnostic LED on the control board visible through a small window. Count the number of blinks in each sequence and match them to the error chart on the inside panel of the furnace door.
Can I reset my HVAC system to clear an error?
You can try turning off the system at the thermostat and breaker for 5 minutes. If the error returns after restart, it indicates a persistent issue that needs professional diagnosis.