Bryant Furnace 13 Error Code: Meaning, Causes & Fix
Limit circuit lockout — lockout occurs if the limit or flame rollout switch is open longer than 3 minutes, or (variable-speed Bryant wording) 10 successive limit trips occurred during high-heat. The control will auto-reset after 3 hours. Bryant's label cross-refers every 13 to code 33 for the diagnosis.
Code 13 is code 33 that did not clear in time — Bryant prints the relationship on every service label ('Refer to status code #33') because 13 has no separate cause list: it is the lockout the limit circuit escalates to. Two documented paths lead here. The clock path: a limit or rollout switch opens (33) and is still open 3 minutes later — the heat is not being carried away, or the switch cannot remake. The count path, worded in the 355MAV guide and the 577D section: 10 successive limit trips during high-heat also produce the lockout, even if each trip remade quickly — the control has counted a furnace that overheats as a pattern, not an accident. Once in 13, gas heating stops: Bryant's documented behaviour is an auto-reset after 3 hours, after which the furnace may try again — and lock out again if the switch is still open or the trips resume. The rollout branch hides inside 13: the flame rollout switch is a manual-reset device, so once tripped it is open forever until a human resets it — a rollout event sails through the 3-minute mark and presents as a 13 lockout with no hot furnace left to feel. The 330JAV label says it in one line under 13: 'Reset switch or replace fuse link.' A 13 on a cold furnace is therefore often a rollout (or a failed switch or connection), while a 13 arriving mid-evening after repeated short heat runs is the airflow story at its end stage. Either way, the 3-hour auto-reset is a safety pause, not a repair — a furnace spending its winter cycling between 33, 13 and a 3-hour wait is being damaged by the pattern, trip by trip.
What causes the 13 code on a Bryant furnace?
The code 33 airflow family, persisted
Everything on Bryant's 33 list that lasts longer than 3 minutes or repeats 10 times in high-heat: dirty filter or restricted duct system first, then the blower family. A marginal restriction producing forgiving 2-minute trips in October produces 13s in January, when runs are longest.
Blower failure — motor, capacitor, or loose wheel
The surest route to the clock-path lockout: if the blower cannot move air at all, the limit opens and cannot remake, because nothing carries the exchanger's heat away. Bryant lists defective blower motor or capacitor and a loose blower wheel on the 33 label 13 inherits.
Flame rollout switch open (manual-reset device)
A tripped rollout switch or an open fuse link stays open indefinitely, so any rollout event becomes a 13 after 3 minutes by definition. Causes live in Bryant's 33 rollout branch: inadequate combustion air supply, restricted vent, or a component failure in the burner compartment.
Firing too hard for the airflow
Input rate set too high, an improper low-heat gas input adjustment, or a stuck high-heat solenoid (355MAV's 33 list): the furnace makes heat faster than a healthy airflow sheds it, trips stack up, and the 10-trip counter reaches the lockout.
Defective switch or connections
A limit switch that has drifted, weakened and begun opening early, or a connection that drops out hot, can hold the circuit open past 3 minutes or manufacture 'trips' the counter believes. Bryant lists it last under 33; it is proven by temperature rise, not assumed.
Vent restriction or excessive wind holding temperatures up
Also inherited from Bryant's 33 list: a restricted or improperly sized vent, or wind pressure at the termination, degrading combustion enough to keep the burner compartment and exchanger hot past the 3-minute line.
Checks to run before you replace anything
- SAFETY: a 13 is a safety lockout on a gas appliance. Never bypass the limit circuit, and never reset a rollout switch before its cause is corrected — Bryant's caution is explicit. Gas smell, soot or scorching at the burner compartment, or a CO alarm: furnace off, licensed technician (gas utility for a gas smell).
- Establish which path brought you here. Did the furnace run heat, trip, recover and repeat all evening (count path / marginal airflow), or did it stop once and never come back (clock path — blower dead, rollout open, or a switch that cannot remake)? The two stories share a code and almost nothing else.
- If the furnace is cold and still shows 13, weight the manual-reset branch: a tripped rollout switch or open fuse link cannot clear itself at any temperature. That check — and any reset — is burner-compartment work for a technician.
- Do the owner checks once, properly: replace the filter, open every register and return, and confirm the blower runs when the control calls it. Then stop: a 13 that returns after honest airflow is a diagnosis, not a reset schedule.
- Read the stored fault history before the auto-reset or any power cycle erases your evidence (on older Bryant boards a power interruption erases stored codes; the Evolution 987M keeps its last 7). A history stacked with 33s before the 13 confirms the count path; a bare 13 points the other way.
- Note the timing pattern for the technician: time of day, outdoor temperature, how long heat ran before the lockout, whether the blower was heard. On limit faults, the pattern is worth more than the code.
How to fix bryant error code 13?
- Fix code 33's cause — that is the whole of 13's repair, by Bryant's own cross-reference. Airflow first: filter, registers, returns, duct restriction corrected at the source.
- Blower branch: replace a defective blower motor or capacitor, refit a loose wheel, correct the speed tap — the lockout cannot clear sustainably while the air-mover is the fault.
- Rollout branch: correct the inadequate combustion air supply, vent restriction or failed component first; then reset the rollout switch or replace the fuse link, as Bryant's label directs. A second rollout trip after a correct repair is a stop-work event.
- Firing branch: a technician resets the input rate / gas input adjustment to the rating plate and deals with a stuck high-heat solenoid — gas work, with a manometer, not a guess.
- Switch branch: replace a proven-defective limit switch or repair its connections — proven, in Bryant's terms, by the temperature rise sitting inside the rating-plate range while the switch still misbehaves.
- Verify the repair across a full, long heating cycle — ideally the kind of run that produced the lockout — not a 3-minute test fire. A furnace that clears 13 and trips again at minute 40 has told you the fix missed.
The part that usually fails: Usually no part — the same airflow or blower fault as code 33, one stage worse; on the manual-reset branch, the rollout switch or fuse link after its cause is fixed
Code 13 inherits 33's parts logic: filter and airflow first, blower motor/capacitor/wheel second, firing and vent corrections third, the switch last and only on a temperature-rise measurement inside the rating-plate range. The lockout adds no new part — it adds urgency, because it certifies the fault persisted or repeated.
How to reset bryant furnace error code 13?
Bryant's documented reset for 13 is time: the control auto-resets after 3 hours, and the furnace may then attempt to run. Two qualifications. First, the rollout branch does not participate in the timer — a manual-reset rollout switch (or open fuse link) must be reset or replaced by hand once its cause is corrected, or the circuit is still open when the 3 hours expire and the lockout re-forms. Second, cycling power restarts the control but fixes nothing: if the switch is still open, the furnace walks back through 33 into 13 in about 3 minutes. One clean retry after a real fix is a test; a daily lockout-and-wait rhythm is the furnace asking for a technician.
Bryant's lockouts run on documented timers, and they are not interchangeable. Limit lockout (13) and ignition lockout (14) auto-reset after 3 hours. Blower motor lockout (15, variable-speed boards) also auto-resets after 3 hours. Control circuitry lockout (45) auto-resets after 1 hour, and Bryant adds: reset power to clear the lockout — if 45 repeats, replace the control. Gas heating lockout (21) is the exception with NO auto-reset: Bryant's instruction is to turn off power and wait 5 minutes to retry. The pressure-switch behaviour under 31/32 (inducer shuts off for 15 minutes after the switch has been open 5 minutes, then retries) is a retry pause, not a lockout. Everything else on the Bryant chart is a condition code that clears when its condition clears: 33 ends when the limit or rollout switch remakes as the furnace cools (the rollout switch itself is manual-reset hardware — no timer resets it, and Bryant requires its cause to be corrected before it is reset), and 24 ends only when the 24-volt short is repaired and the fuse replaced. Interrupting power restarts a Bryant control, but on the older boards it also erases the stored fault history — read the history first, and never treat a cleared timer as a repaired furnace: an unfixed cause simply walks the control back into the same lockout.
Why does bryant furnace error code 13 keep coming back?
A 13 that returns after its 3-hour auto-reset is a furnace reporting that nothing changed while it waited — because nothing did. Recurring 13s concentrate on the coldest nights (longest runs, weakest airflow), each cycle another set of overheating trips on the heat exchanger. A 13 appearing on mild days after a winter of cold-day 13s is the restriction or blower worsening on schedule; treat the pattern as a deadline, not a personality trait.
How to stop 13 coming back
- The code 33 airflow family, persisted: Everything on Bryant's 33 list that lasts longer than 3 minutes or repeats 10 times in high-heat: dirty filter or restricted duct system first, then the blower family. A marginal restriction producing forgiving 2-minute trips in October produces 13s in January, when runs are longest.
- Blower failure — motor, capacitor, or loose wheel: The surest route to the clock-path lockout: if the blower cannot move air at all, the limit opens and cannot remake, because nothing carries the exchanger's heat away. Bryant lists defective blower motor or capacitor and a loose blower wheel on the 33 label 13 inherits.
- Flame rollout switch open (manual-reset device): A tripped rollout switch or an open fuse link stays open indefinitely, so any rollout event becomes a 13 after 3 minutes by definition. Causes live in Bryant's 33 rollout branch: inadequate combustion air supply, restricted vent, or a component failure in the burner compartment.
Retrieving stored fault codes on Bryant furnaces
Every Bryant status code in these manuals is a two-digit number read off the status LED at the indicator in the blower door: the first digit is the number of SHORT flashes, the second digit the number of LONG flashes (33 = three short, three long). Three steady states frame the codes: LED continuously ON means the control has 24 VAC power; continuously OFF means check for 115 VAC at L1 and L2 and 24 VAC at SEC-1 and SEC-2; RAPID flashing means line-voltage polarity is reversed. Stored history is played back, not guessed — and the method is generation-specific. On the oldest labels (330JAV/393AAV), briefly remove and reconnect one main limit wire without removing power or the blower door; those boards erase stored codes when power is interrupted or 48 hours after each fault is cleared. The 340AAV red-LED boards and the variable-speed 355MAV erase stored codes automatically after 72 hours; the 355MAV recalls history by disconnecting the R lead (or the ABCD User Interface connector), resetting power and putting setup switch SW1-1 ON, and clears it by jumpering R, W/W1 and Y/Y2 simultaneously until code 11 flashes. The Evolution 987M changed the rule: its stored codes are NOT erased when 115- or 24-volt power is interrupted — the control stores up to the last 7 status codes in order of occurrence; with no thermostat signal present and all blower-off delays complete, set SW1-1 ON and the control flashes up to 7 codes, the 8th code always being 11, and a continuously lit amber LED afterwards confirms proper operation. On Evolution systems the Connex wall control adds its own reporting layer on top of the board: a Last 10 Events record and service screens — including Furnace Status, and, on compatible models, an Advanced Diagnostics view naming the most likely root causes of the most recent fault. The component test (setup switch SW1-6) runs the inducer, igniter and blower in sequence and reports back in codes (11, 25, 41 and 42 on the 355MAV; 11, 25, 35, 41 and 42 on the 987M). Whatever the generation, the service label printed inside your own Bryant's blower door is the chart of record for that furnace.
Other Bryant furnace error codes
| Code | Meaning | First fix |
|---|---|---|
| 11 | No previous code — not a fault: 11 is the end marker of the stored-history playback, showing no fault is stored (or none remains) | No repair needed. Bryant's label directs: run the system through a heating or cooling cycle to check it |
| 12 | Blower on after power up — normal operation, not a fault: the blower runs 90 seconds when the furnace is powered up during a call for heat (R–W closed), or the call ends during the blower on-delay | No repair needed. If 12 shows with no power event and no heat call, have the thermostat call and control checked |
| 14 | Ignition lockout — the system failed to ignite gas and prove flame in 4 attempts (the trial plus code 34's three retries). The control auto-resets after 3 hours | Do not keep resetting it. Diagnose as code 34 (see the ignition codes guide); gas and flame-sense work is licensed-technician work |
| 15 | Blower motor lockout (variable-speed boards) — the blower failed to reach 250 RPM, or to communicate within 30 seconds of switch-on, in two successive heating cycles. Auto-resets after 3 hours | Technician work — code 41 twice in a row. The repair is the proven blower, wiring or control, not another reset |
| 21 | Gas heating lockout — the control has locked out of gas heating and will NOT auto-reset. Bryant: turn off power and wait 5 minutes to retry | Power off, wait 5 minutes, retry once only. A returning 21 is a control or gas-valve wiring fault — licensed-technician work |
| 22 | Abnormal flame-proving signal — flame is proved while the gas valve is de-energised. The inducer runs until the fault is cleared | Do not run the furnace. Technician test: shut the external manual gas valve — if 22 stops, the gas valve is replaced; if not, sensor or control |
| 23 | Pressure switch did not open — a switch contact is still made (closed) when a call for heat begins, before the inducer runs; the control flashes 23 until the switch opens, then the cycle can begin | Never bypass the switch. A technician clears or replaces the tubing and replaces a switch that stays made |
| 24 | Secondary voltage fuse is open — the fuse protecting the control's 24-volt (secondary) circuit has opened because there is a short circuit in the secondary-voltage wiring. On the Evolution 987M the fuse is an automotive-type 3-amp fuse located on the control, and Bryant states the control LED will display status code 24 when the fuse needs to be replaced. | Repair or replace the shorted wire run — thermostat cable, limit-circuit wiring, pressure-switch wiring, gas valve lead or accessory (humidifier) circuit, as the isolation proves; a humidifier solenoid or diode bridge drawing excessively is replaced. A wire that has chafed through once is replaced or properly re-insulated and re-routed, not taped against the same edge. |
| 25 | Model selection or setup error (variable-speed/Evolution boards) — the model plug (PL4) is missing or incorrect, or a setup switch is misplaced. If 25 flashes only 4 times on power-up, the control is defaulting to the model stored in memory and runs as if the plug were fitted | Technician work: fit the correct plug for the exact model (per the wiring diagram; read only on power-up) and return setup switches to OFF |
| 31 | Pressure switch did not close or reopened — on two-stage/variable-speed boards, the HIGH-heat switch (or its relay); single-stage boards print the same 31 for their one switch. Open over 5 minutes: the inducer shuts off 15 minutes before retry | Clear the outdoor vent/intake terminations first. Draft, switch and inducer diagnosis is technician work — never jumper the switch |
| 32 | Low-heat pressure switch did not close or reopened (two-stage/variable-speed boards; the label also covers the draft safeguard or aux-limit switch where used). Opens within 5 minutes after ignition: the next cycle is restricted to high-heat | Clear terminations and check the condensate trap/drain on condensing models; the rest is measured draft and switch diagnosis by a technician — never jumper it |
| 33 | Limit circuit fault — a limit switch or flame rollout switch in the limit circuit is open. The blower runs for 4 minutes or until the open switch remakes, whichever is longer; open longer than 3 minutes, the code changes to lockout 13; remade sooner, 33 keeps flashing until the blower shuts off. The rollout switch requires manual reset. | Restore airflow: new filter, all registers and returns open, and the duct restriction corrected at its source. |
| 34 | Ignition proving failure — flame was not sensed during the trial-for-ignition period. The control repeats the sequence 3 more times before lockout 14; a flame signal lost in the blower on-delay brings the blower on for the off-delay | Confirm the gas valve and shut-off are on; sensor (cleaned with fine steel wool), igniter, pressure and ground checks are technician work — see the ignition guide |
| 41 | Blower motor fault (variable-speed boards) — the blower failed to reach 250 RPM, or to communicate within the time limits: 30 seconds after switch-on, 10 seconds in steady-state operation. In the component test, 41 means the blower failed the test | Technician work: prove wheel freedom, wiring and control before replacing motor or module. Two successive cycles of 41 escalate to lockout 15 |
See the full list on the Bryant Furnace error codes hub.
Codes 13 gets confused with
33 — Limit circuit fault — a limit switch or flame rollout switch in the limit circuit is open. The blower runs for 4 minutes or until the open switch remakes, whichever is longer; open longer than 3 minutes, the code changes to lockout 13; remade sooner, 33 keeps flashing until the blower shuts off. The rollout switch requires manual reset. Code 33 is Bryant's overheating-and-rollout report, with identical wording across the whole Bryant line — limit or flame rollout switch open, blower runs 4 minutes or until the switch remakes, 3 minutes to lockout 13 — printed on the single-stage 340AAV, 330JAV and 393AAV service labels, in the 577D control section, and in the variable-speed 355MAV guide.
24 — Secondary voltage fuse is open — the fuse protecting the control's 24-volt (secondary) circuit has opened because there is a short circuit in the secondary-voltage wiring. On the Evolution 987M the fuse is an automotive-type 3-amp fuse located on the control, and Bryant states the control LED will display status code 24 when the fuse needs to be replaced. Code 24 is the Bryant control protecting itself, and it starts with what 'secondary voltage' means: the transformer steps line voltage down to the 24 VAC that runs everything the furnace thinks with — thermostat circuit, limit circuit, pressure switches, gas valve, and accessories such as the humidifier terminal.
Frequently asked questions
What does code 13 mean on a Bryant furnace?
Limit circuit lockout. It occurs if the limit or flame rollout switch is open longer than 3 minutes, or — in the variable-speed Bryant wording — after 10 successive limit trips during high-heat. The control auto-resets after 3 hours. Bryant cross-refers 13 to code 33 for the diagnosis: overheating from restricted airflow, blower trouble, venting, combustion air or firing rate.
Will Bryant code 13 clear itself?
The lockout will: Bryant documents an auto-reset after 3 hours. But 'clear' is not 'fixed' — if the switch is still open or the airflow still restricted, the furnace returns to 13, and the manual-reset rollout switch never clears on any timer: it must be reset (or its fuse link replaced) after its cause is corrected. A 13 that clears and returns is reporting, not healing.
Why does my Bryant furnace show 13 when it isn't even hot?
Because one branch of the limit circuit is a manual-reset device. The flame rollout switch, once tripped, stays open at any temperature until it is reset by hand — so its event passes the 3-minute mark and shows as lockout 13 on a stone-cold furnace. A failed limit switch or an open connection in the circuit tells the same lie. A cold 13 is a continuity diagnosis, not an overheating one — technician work.
How do I fix Bryant code 13?
The way Bryant structures it: 13 has no fix list of its own — the label says 'Refer to status code #33'. Work 33's list in order: filter and duct restriction, blower motor/capacitor/wheel, venting and combustion air, input rate, switch last. If the rollout switch or fuse link is the open device, its cause is corrected first and the switch reset or link replaced second, by a technician.
Is it safe to keep waiting out the 3-hour reset on code 13?
No. The auto-reset exists so a transient event does not leave a house cold forever — not as an operating mode. Every limit trip is an overheating event for the heat exchanger, and a furnace needing the 3-hour pause regularly is accumulating thermal damage while reporting that its airflow, blower, venting or firing is wrong. Two lockouts in a season is the call-a-technician line.
How to fix bryant error code 13?
Start here: Fix code 33's cause — that is the whole of 13's repair, by Bryant's own cross-reference. Airflow first: filter, registers, returns, duct restriction corrected at the source. Blower branch: replace a defective blower motor or capacitor, refit a loose wheel, correct the speed tap — the lockout cannot clear sustainably while the air-mover is the fault.
What does bryant furnace error code 13 mean?
Limit circuit lockout — lockout occurs if the limit or flame rollout switch is open longer than 3 minutes, or (variable-speed Bryant wording) 10 successive limit trips occurred during high-heat. The control will auto-reset after 3 hours. Bryant's label cross-refers every 13 to code 33 for the diagnosis. Code 13 is code 33 that did not clear in time — Bryant prints the relationship on every service label ('Refer to status code #33') because 13 has no separate cause list: it is the lockout the limit circuit escalates to.
How to reset bryant furnace error code 13?
Bryant's documented reset for 13 is time: the control auto-resets after 3 hours, and the furnace may then attempt to run. Two qualifications. First, the rollout branch does not participate in the timer — a manual-reset rollout switch (or open fuse link) must be reset or replaced by hand once its cause is corrected, or the circuit is still open when the 3 hours expire and the lockout re-forms. Second, cycling power restarts the control but fixes nothing: if the switch is still open, the furnace walks back through 33 into 13 in about 3 minutes. One clean retry after a real fix is a test; a daily lockout-and-wait rhythm is the furnace asking for a technician.
Why does bryant furnace error code 13 keep coming back?
A 13 that returns after its 3-hour auto-reset is a furnace reporting that nothing changed while it waited — because nothing did. Recurring 13s concentrate on the coldest nights (longest runs, weakest airflow), each cycle another set of overheating trips on the heat exchanger. A 13 appearing on mild days after a winter of cold-day 13s is the restriction or blower worsening on schedule; treat the pattern as a deadline, not a personality trait.
Related guides
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