On the Carrier variable-speed, two-stage furnaces covered by Carrier's guide TG-GFC80-02, the control board has an amber LED that reports the furnace's state. Continuous ON means the control has 24 volts. Continuous OFF means to check for 115 volts at L1 and L2 and 24 volts at SEC-1 and SEC-2. Rapid flashing means the line-voltage polarity is reversed or the transformers are out of phase on twinned units. A slow flash pattern is a two-digit status code: the first digit is the number of short flashes and the second digit is the number of long flashes, so one short and one long flash is code 11. This site lists Carrier codes 11 to 45 with the meanings from Carrier's own guide. The board keeps the last codes for 72 hours.
What this covers
- Carrier furnaces whose control board flashes a two-digit status code on an amber LED
- Codes 11, 12, 13, 14, 15, 21, 22, 23, 24, 25, 31, 32, 33, 34, 41, 43 and 45 as listed in Carrier's guide for the covered models
- Reading and recording the light, not repairing the furnace
What it does not cover
- ×Other Carrier boards whose door label lists different codes
- ×Bryant, Payne or other brands' boards unless their own literature prints the same table
- ×Removing the blower access panel, setting SW1 switches, jumpering thermostat terminals or any live testing
Try in this order
0 of 6 completedIdentify the exact furnace first
ReversibleRead the model number on the rating plate. Carrier's guide covers the 58CVA and 58CVX, and its 59TP6B installation manual prints the same LED table. A different furnace can use a different code list, and the label on your furnace is the authority.
Read the steady states
ReversiblePer Carrier's LED table: continuous OFF means check for 115 volts AC at L1 and L2 and 24 volts AC at SEC-1 and SEC-2. Continuous ON means the control has 24 volts AC power. Rapid flashing without a pause means the 115-volt polarity is reversed, or on twinned furnaces the transformers are out of phase.
Count the short and long flashes
ReversibleA status code is a two-digit number. The first digit is the number of short flashes and the second digit is the number of long flashes. One short and one long flash is 11. Watch two full repetitions, and record the numbers rather than the colors alone.
Use the code list for the meaning
ReversibleLook the code up on this site's Carrier furnace code list. 13 is a limit-circuit lockout, 14 an ignition lockout, 23 a pressure switch that did not open, 24 an open secondary-voltage fuse, 32 a low-heat pressure switch that did not close, 33 a limit-circuit fault, 34 an ignition-proving fault and 41 a blower-motor fault. Each page says which steps are yours and which are a technician's.
Understand what the code history means
ReversibleCarrier says stored codes are erased after 72 hours, and that a technician can recall the last codes by disconnecting the thermostat R lead, cycling power and turning setup switch SW1-1 on, at which point the LED flashes them in order of occurrence and ends with code 11. That is not a customer procedure.
Give the code to a technician
ReversibleTell the service company the furnace brand and model and the exact two-digit code, plus when it appeared and whether it repeats. A lockout code such as 13 or 14 resets by itself after 3 hours per Carrier, but that does not fix the cause.
Evidence ledger
Sources behind this answer
Carrier's own guide for the 58CVA and 58CVX. Two-digit status codes flashed on an amber LED, each with its own section.
Carrier's own manual for the 59TP6B furnace. Its LED table gives the meaning of a continuous off, continuous on and rapid-flashing light, and prints status codes 11 to 14.
Exact questions
Common questions about “How to read a Carrier furnace status-light code”
Which digit is the short flashes and which is the long ones?+
Carrier's guide says the first digit is determined by the number of short flashes and the second digit by the number of long flashes. Two short flashes followed by three long flashes is code 23.
What does status code 11 mean on a Carrier furnace?+
It means no stored fault. Carrier says stored codes are erased after 72 hours or can be cleared by a technician, and that code 11 also appears after a successful component test.
Does the same code mean the same thing on a Bryant or Payne furnace?+
Do not assume so. This site's Carrier list is taken from Carrier's guide for the models it covers. Other brands' boards print their own table on the furnace door or in their own literature.
Why does my furnace flash rapidly with no pause?+
Carrier says rapid flashing means the 115-volt polarity is reversed, or on twinned units the transformers are out of phase. It is a wiring condition for a technician.
Where is the Carrier status light?+
Most Carrier furnaces have a small window on the blower or control-board door where an LED shows steady, flashing or off patterns. The panel label lists what each pattern means.
Should I open the furnace to read it?+
Only remove the access panel as the manual allows, with the power off first. Many models show the light through a small sight glass without removing anything.
What if the pattern is not on the label?+
Different models use different tables, so read the label on your own unit or find the model's manual. A homeowner should not guess at a code.