Carrier furnaces help keep your home comfy and cozy all season long. But when something’s not right, you’re going to have to figure out what the problem is quickly. Luckily, all Carrier furnaces have their error codes posted to the unit itself, but sometimes they can be confusing. We’ll break down all the possible Carrier furnace error and light codes so you know how to handle the situation.
Carrier Error Codes & Meanings
There are a number of error codes on this list that can easily be solved by the homeowner; however, if you do not feel comfortable completing these tasks, contact your local authorized HVAC service technician.
Note: if you smell gas, leave your house immediately and call your local gas company, authorized HVAC technician or fire department. Do not turn any electrical devices or switches on or off.
Error Code Number
|
Error Code Meaning
|
Solution
|
11 |
No faults detected in recent history
|
Stored codes will be erased when power to system is interrupted
|
12 |
- Blower is on after start-up (gas furnaces)
- Blower calibration lockout (electric furnaces)
|
- Occurs when furnace is powered up during a call for heat (when heat setting has been initially turned on). Blower will run for 90 seconds.
- RPM calculated for low heat wasn’t within normal range. Furnace will auto-reset after 3 hours.
|
13 |
Limit circuit/switch lockout
|
Will auto-reset after 3 hours. If problem persists, check solutions for Error 33.
|
14 |
Ignition lockout
|
Control will reset after 3 hours. If problem persists, check solutions for Error 34.
|
21 |
- Gas heating lockout (gas furnaces)
- Invalid model selection (electric furnaces)
|
- Control won’t auto-reset. Call authorized HVAC technician.
- Model plug is missing or incorrect. Call authorized HVAC technician.
|
22 |
- Gas furnaces: Abnormal flame-proving signal; flame is proved (ready) while gas valve is de-energized. May be caused by stuck-open gas valve or leaky valve.
- Electric furnaces: Setup error; setup switch is positioned incorrectly.
|
- Call authorized HVAC technician.
- Call authorized HVAC technician.
|
23 |
- Gas furnaces: Pressure switch didn’t open
- Electric furnaces: Invalid blower airflow selection likely cause by incorrect A/C or CF switch setting.
|
- Check for any obstructions, damage or disconnections around pressure tubing and pressure switch. If needed, call authorized HVAC technician.
- If code is flashing, furnace will default to closest allowable airflow.
|
24 |
Secondary voltage fuse is open. Possible short circuit occurred.
|
Contact authorized HVAC technician.
|
31 |
Switch in unit didn’t close or open properly. Switches include: pressure, auxiliary-limit, safeguard, high limit or blocked vent shutoff.
|
Relay may be defective. Call authorized HVAC technician.
|
32 |
Low pressure switch fault
|
- Gas furnaces: Check for obstructed vents, excessive wind, obstructed or disconnected pressure tubing. Call authorized HVAC technician.
- Electric furnaces: Check for obstructed condensate drain or water in vent piping. If both seem fine, call authorized service technician.
|
33 |
Limit or flame roll-out switch is open
| Check filter, filter housing and duct system. Clean or replace filter and any dust or dirt around airflow openings. |
34 |
Ignition proving failure
|
- Flame sensor may be dirty. Clean with steel wool.
- Check gas valve. May be defective or turned off.
- If issue persists or code changes to Error 14, call authorized HVAC technician.
|
41 |
Blower’s turning too slow or too fast
|
Call authorized HVAC technician
|
42 |
Inducer’s operating too slow or too fast
|
Check for plugged condensate drain or water in vent. If both seem fine, call authorized service technician.
|
43 |
Pressure switch issue due to blockage or disconnection
|
- Gas furnaces:
- Check for blockages or disconnections with pressure tubing and correct as needed.
- If issue still persists, call authorized HVAC technician.
- Electric furnaces:
- Check for blockages or disconnections in condensate drain or vent piping and correct as needed.
- If issue still persists, call authorized HVAC technician.
|
44 |
Blower calibration issue. Blower speed is too low or too high.
|
Check filter and replace if necessary. If Error 41 also appears, call authorized HVAC technician.
|
45 |
Control lockout |
Turn furnace off and turn to reset and clear lockout. If error code repeats, call authorized HVAC technician.
|
LED Light Code Meanings
Many Carrier furnaces will have different LEDs that indicate the current status of your unit. If your furnace has these and are illuminated or flashing, take a look at the chart below to see what they mean.
LED Code
|
Status Meaning
|
Continuously OFF
|
Voltage needs to be checked
|
Continuously ON
| Control has power |
Rapidly flashing
| Line voltage polarity reversed; furnace isn’t grounded |
Red LED 1 is ON
|
Furnace is operating on emergency heat
|
Red LED 2 is ON
|
Microprocessor malfunction. Needs to be reset
|
Red LED 2 is FLASHING
|
Line voltage polarity reversed; furnace isn’t grounded
|
Yellow LED 3 is ON
|
Furnace is operating on high heat
|
Green LED 4 is ON
| Furnace is operating on low heat |
For additional troubleshooting tips, cleaning instructions or operating guidelines for your Carrier furnace, take a look through our collection of Carrier manuals for help.
Please contact a local authorized service agent who can help with this specific unit and all your heating and cooling needs.
