Carrier · Status code
Carrier 59TN7A status code 13: limit lockout or ignition lockout
Major code 13 covers two lockouts on the 59TN7A control. Minor code 13.1 means a switch in the main limit circuit stayed open for more than three minutes, so the control locked out. Minor code 13.2 means the ignition sequence failed four consecutive times and the control locked out. Both require a reset condition to clear.
Smell gas?
- Do not operate light switches, appliances or phones inside.
- Leave the building and leave the door open behind you.
- From outside, call the FortisBC emergency line at 1-800-663-9911 or 911.
- Only after that, call BC Wide about the furnace.
A furnace that will not run is a breakdown, not a gas emergency. Gas smell, a CO alarm, soot or scorching are.
On the control
- Code
- 13
- Minor
- 13.1 · 13.2
- Door LED
- 1 short flashes then 3 long
- Controller
- 59TN7A integrated furnace control with 3-digit LCD display and door LED
- Applies to
- Carrier Infinity 97 (59TN7A)
- Manual
- 59TN7A-01SI
What each minor code says, verbatim
| Display | Manufacturer wording |
|---|---|
| 13.1 | Limit Lockout - switch open longer than 3 minutes in Main Limit circuit |
| 13.2 | Ignition Lockout after 4 consecutive ignition tries |
A code is a condition, not a diagnosis
A limit lockout (13.1) is a symptom of overheating somewhere in the airflow path: a loaded filter, closed registers, undersized ducts, a blower that is not running or not moving rated airflow, or a furnace oversized for the ducts. It can also be the rollout side of the circuit responding to a combustion problem. An ignition lockout (13.2) means the control never proved flame: gas supply, ignitor, flame sensing, gas-valve operation or combustion-air problems all produce it. Only on-site testing separates these causes.
Which furnaces this applies to
Documented for Carrier 59TN7A furnaces (all nine sizes) in installation instructions 59TN7A-01SI REV A, edition 06/23. The main limit circuit includes the furnace limit switches; the manual-reset limit switch in the burner assembly opens on an overheat (flame rollout) condition and must never be bypassed.
Scope: Carrier 59TN7A Infinity 97 furnaces with the on-board 3-digit display control. Not sure which control you have? Send us the full model number from the rating plate.
Safe things to look at first
- Read the full code on the control display through the door, including any minor digit (for example 33.2), and write it down.
- Look, without touching, for obvious conditions you can report: snow or ice at the vent terminations, water on the floor, a loaded filter, a condensate pump that is full or off.
- Note whether the furnace still heats at all, and how long it runs before the code returns.
- For 13.1: check whether the blower is running at all and whether the filter is loaded; note any warm smell near the furnace.
- For 13.2: confirm the gas shut-off valve is fully on and note whether you can hear the inducer run before the code appears.
- If you smell gas at any point, leave the building and call FortisBC at 1-800-663-9911 or 911 first.
Do not
- Do not bypass or jumper the door switch, limit switches, rollout switches or pressure switches.
- Do not open the burner compartment, disconnect tubing, or adjust the gas valve or gas pressure.
- Do not keep cycling power to force the furnace to relight; repeated resets hide the fault and can allow unburned gas to build up after ignition failures. If the code returns, stop and call.
Homeowner-safe checks (look and read only)
- Check that the filter is not loaded and supply registers are open
- Confirm the blower door is fully seated
- Look, without touching, for water around the furnace and ice at the vent terminations
- If you smell gas or a CO alarm sounds, leave and call FortisBC at 1-800-663-9911 or 911
When to call a technician
- If the code returns after one power reset
- Immediately, if you smell gas or a CO alarm sounds
Also documented on the same controller family: Carrier Performance 97 (59TP7A).
What a technician does
- A technician measures temperature rise and static pressure, checks the filter, blower and duct path, and verifies every switch in the main limit circuit before resetting.
- For an ignition lockout the technician checks gas supply pressure, the hot-surface ignitor, flame sensor signal, gas valve operation and the venting before clearing the fault history.
- A manual-reset rollout switch that has opened must be reset only after the cause is found and corrected; Carrier's instructions are explicit that the switch must not be jumpered.
Same code, other equipment
- Older Carrier LED-only controls: Earlier 59TP6A/59TP6B controls use LED flash codes from their own manuals; do not assume code 13 means the same thing there.
Related components and symptoms
Questions people ask
Can I reset a 13 lockout myself?
Carrier's instructions allow the control to retry after lockout conditions clear, but if the code returns, repeatedly resetting is exactly what the manual warns against. The cause must be found; a limit circuit that stays open is the furnace protecting itself from overheating.
Does code 13 mean my heat exchanger failed?
Not by itself. A limit lockout usually points to airflow, and an ignition lockout to the ignition sequence. A technician tests before any part is replaced.
Why would 13.2 appear only in cold weather?
Cold-weather ignition failures often trace to condensate freezing in the vent or drain, or a vent termination icing over, which starves or blocks combustion. Those show up as ignition or pressure-switch faults.
Seeing code 13 on your Carrier?
Tell us the full code, the model number and whether the furnace still heats on low. BC Wide prioritizes no-heat calls across Greater Vancouver.