How to Reset Bryant Furnace Error Codes

Bryant furnaces reset in three different ways depending on what reported the fault: condition codes (like 33 and 24) clear when their condition is fixed; timed lockouts (13, 14, 15 and 45) clear on Bryant's documented clocks; and one lockout (21) never clears itself at all. This guide sets out each mechanism with Bryant's own timings, explains the power-cycle reset and what it costs you on older boards (your stored fault history), shows how to read that history three ways — blower-door playback, setup switch, and the Evolution Connex wall control — and names the codes Bryant's literature says not to reset-and-run: anything in the limit and rollout family.

How Bryant codes clear: condition codes first, lockouts second

The most useful reset fact about a Bryant furnace is that most of its codes are not lockouts and have no reset procedure at all — they are live reports that end when the reported condition ends. Code 33 (limit circuit fault) flashes while a limit or rollout switch is open and ends when the switch remakes as the furnace cools, with the control running the blower for 4 minutes or until remake, whichever is longer. Code 23 flashes until the stuck pressure switch opens. Code 34 is a failed ignition attempt that the control is already retrying on its own, up to four attempts. Code 24 cannot clear by any button or timer: it ends when the 24-volt short is repaired and the fuse replaced. Against those, the true lockouts are a short list with clocks attached. Limit lockout 13 and ignition lockout 14 auto-reset after 3 hours. Blower motor lockout 15 (variable-speed boards) auto-resets after 3 hours. Control circuitry lockout 45 auto-resets after 1 hour, and Bryant adds a manual exit: reset power to clear it. Gas heating lockout 21 stands apart — Bryant prints 'Control will NOT auto reset' on every label, with the instruction to turn off power and wait 5 minutes to retry. Knowing which family your code belongs to tells you whether waiting is a strategy at all: waiting out a condition code whose condition persists (a 33 with a clogged filter) accomplishes nothing, because the code is not a punishment counting down — it is a measurement still being taken. The sections below take each reset mechanism in turn.

The power-cycle reset — what it does, and what it erases

Interrupting power is a real Bryant reset, and the manuals document it in precise places: the 355MAV sequence of operation states that ignition lockout is reset 'by momentarily interrupting 115 vac power to the furnace, or by interrupting 24 vac power at SEC1 or SEC2 to the furnace control', and code 45's instruction is simply 'reset power to clear lockout'. A power cycle also restarts any Bryant control out of a latched state — once. What the manuals also document, and what most reset advice omits, is the price on the older generations: stored status codes are erased when power (115V or 24V) to the control is interrupted. That is printed on the 330JAV and 393AAV labels, with the companion rule that stored codes also erase 48 hours after each fault is cleared; the 340AAV red-LED boards erase after 72 hours and likewise on power interruption. So on those furnaces, the instinctive 'turn it off and on again' deletes the furnace's own record of what it has been doing — the stack of 33s behind a 13, the intermittent 24s, the 34s creeping toward 14 — at the exact moment you most need to read it. The Evolution 987M is the documented exception, and Bryant calls the difference out in its own text: on the 987M, 'the stored status codes will NOT be erased from the control memory, when 115- or 24-v power is interrupted', and the control stores up to the last 7 status codes in order of occurrence. The disciplined Bryant reset procedure is therefore: read and record the active code AND the stored history first (next sections), make the fix the code actually names, then cycle power once as a test — and let a full heating cycle, not the cleared display, be the verdict.

Lockout auto-reset timing, code by code

Bryant's clocks, collected from the service labels and the troubleshooting guide, are these. THREE HOURS: code 13 (limit circuit lockout — a limit or rollout switch open longer than 3 minutes, or 10 successive limit trips in high-heat on the variable-speed wording); code 14 (ignition lockout, after 4 failed ignition attempts); code 15 (blower motor lockout, after the blower failed to reach 250 RPM or communicate in two successive heating cycles). After the 3 hours, the control auto-resets and the furnace may try again — and, if the cause stands, lock out again; the timer buys an opportunity, not an outcome. ONE HOUR: code 45 (control circuitry lockout — flame sense circuit failure, gas valve relay stuck open, or software check error), which also clears immediately by resetting power; Bryant's closing instruction for 45 is the one to respect: 'Replace control if status code repeats' — a 45 that returns after its reset has exhausted the reset conversation entirely. NEVER: code 21 (gas heating lockout) has no auto-reset on any Bryant label; the documented retry is to turn off power, wait 5 minutes, and retry — and because 21's causes are a stuck-closed gas valve relay on the control or a miswire/short to the gas valve wire, that retry is a single diagnostic act, not a routine. NOT A LOCKOUT, but often mistaken for one: the pressure-switch retry under codes 31/32 — if the switch stays open longer than 5 minutes, the inducer shuts off for 15 minutes before retry. That pause is the control pacing its inducer, and it repeats as long as the vent will not prove; there is no number of 15-minute pauses after which persistence becomes safe, only a vent path asking to be cleared. And the manual-reset hardware that outranks every clock: a tripped flame rollout switch (or open fuse link) does not participate in any timer — it is reset by hand, after its cause is corrected, or replaced.

Reading stored fault history: blower door, setup switch, and the Evolution Connex

Bryant gives you three doors into the furnace's memory, and which one fits depends on the generation. The chart of record comes first, always: the service label printed inside the blower door carries your exact model's code table — photograph it once and you will never read a code against the wrong generation's chart. For the history itself, the oldest method in this check (330JAV/393AAV labels) is disarmingly simple: if status code recall is needed, do not remove power or the blower door — briefly remove and then reconnect one main limit wire, and the control displays the stored status code. The variable-speed method (355MAV) is a setup-switch procedure: disconnect the R thermostat lead (or the ABCD User Interface connector on communicating systems), reset power, and put setup switch SW1-1 in the ON position — the stored codes flash in the order of occurrence until code 11 flashes, after which the sequence repeats; those codes erase automatically after 72 hours, and the history can be deliberately cleared by putting SW1-1 ON and jumpering the R, W/W1 and Y/Y2 terminals simultaneously until 11 flashes. The Evolution 987M method is the same switch with better memory: no thermostat signal may be present and all blower-off delays must be completed; leave 115-volt power ON, open the blower door, set SW1-1 ON, manually close the blower door switch — the control flashes up to 7 stored codes, and the last (8th) code will be 11; set SW1-1 OFF and a continuously lit amber LED confirms proper operation. On a full Evolution system there is also the wall: the Connex control keeps a Last 10 Events record and offers service screens including Furnace Status and, on compatible models, Advanced Diagnostics naming the most likely root causes of the most recent fault. Whichever door you use, write the codes down in order before clearing anything — the order is the story, and a cleared history cannot be un-cleared.

The setup switches are service tools, not reset buttons

The same setup switches that read Bryant's history deserve a warning of their own, because they sit on the control where a curious hand can reach them, and Bryant's manuals treat their positions as configuration, not as user controls. SW1-1 is the history/component-test switch used throughout the previous section; SW1-6 initiates the component test. Left in the wrong position, they change what the control does — and Bryant's code 25 (model selection or setup error) names the collision explicitly: a thermostat call arriving with SW1-1 ON, a thermostat call with SW1-6 ON, or both switches ON together are all listed causes of a flashing 25. In other words, the furnace has a code whose whole job is to report that someone left a service switch on. The model plug belongs in the same warning: it is the small plug (PL4) that tells a replacement control which furnace it is running, it is read only on power-up, and a missing or wrong plug is the other half of code 25 — four flashes of 25 on power-up even means the control is running on the model stored in memory because the plug is absent. None of these are reset levers, and 'trying the dip switches' on a faulted Bryant is a reliable way to trade a readable code for a setup error stacked on top of it. The correct use of everything in this section is the technician's: retrieve the history with SW1-1, run the evidence down, and return every switch to OFF and every wire to its terminal before the blower door goes back on — which is also why Bryant's retrieval procedures end, every time, with exactly that instruction. If your furnace shows a 25 after any service visit, that is the first thing to report: it usually means the visit's tools were left switched on, and the fix is a position, not a part.

What NOT to reset repeatedly: the limit and rollout family

Bryant's literature singles out one reset as a genuine hazard, and it is worth quoting its logic in full. The flame rollout switch is a manual-reset device in the burner compartment, and the 355MAV guide's caution reads: the switch will open and shut off power to the gas valve if a flame rollout or overheating condition occurs in the gas control area — 'DO NOT bypass the switch. Correct inadequate combustion-air supply, component failure before resetting the switch.' Before operating the furnace, each manual reset switch is to be checked for continuity, and reset — press and release the button — only as part of that correction. The service label under code 13 says the same thing in shorthand: 'Reset switch or replace fuse link.' A rollout reset into uncorrected conditions is not a reset at all; it is re-arming a furnace whose flame has already left the burner box once. The limit codes sit one rung below that, and the same discipline applies in softer form. A 33 that is power-cycled away without its airflow fix will return; a 33 allowed to mature into 13 repeatedly is a heat exchanger being thermal-cycled by its own safety system, trip after trip, season after season. Bryant's control counts the pattern even when owners do not — 10 successive limit trips in high-heat is itself a documented path into the 13 lockout — which is the manufacturer's way of stating this page's rule: two appearances of the same safety code in one heating season is a diagnosis, not a reset schedule. If you find yourself knowing a reset procedure by heart, the procedure has become the problem it was meant to report.

When the reset works but the furnace is still telling you something

Some Bryant resets succeed completely — the code clears, the furnace runs — and are still reports worth acting on, because Bryant's controls remember patterns that displays forget. A 45 that clears with a power reset and returns a month later is, per Bryant's own closing line for the code, a control announcing its replacement in instalments: 'Reset power to clear lockout. Replace control if status code repeats.' A 24 that clears with a new fuse is a short circuit that happened once and will happen at the same chafe point again unless the wire, contactor or solenoid behind it was found — the fuse is a consumable only in the sense that it consumes itself instead of the board. An ignition lockout 14 that clears at its 3-hour mark on a night the gas supply was interrupted is the system working as designed — and the same 14 appearing weekly with the supply proven is an igniter or flame sensor ending its service life on a schedule you can set a calendar by. Even the humble 12 (blower on after power up) is data: it timestamps a power interruption mid-call, which is why a furnace 'mysteriously' running its blower after a storm is usually just Bryant's 90-second power-up behaviour, not a new fault. The habit that turns resets into reliability is a notebook — code, date, outdoor temperature, what the furnace was doing, what you changed. Bryant's controls keep 7 codes on an Evolution and a 72-hour window on the older boards; your notebook keeps the whole season, and it is the document that lets a technician see in one glance whether your furnace had an incident or is developing a condition.

Key takeaways

• Read before you reset: record the active code and the stored history first — on Bryant boards older than the Evolution 987M, the power cycle that clears the lockout also erases the history, permanently.
• Learn your lockout's clock before waiting on it: 13, 14 and 15 give you 3 hours; 45 gives you 1 hour (or a power reset); 21 never auto-resets; and a tripped rollout switch answers to no timer at all.
• A reset is a test with a budget of one: fix the named cause, reset once, and judge by a full heating cycle. A code that returns after an honest fix has completed the diagnosis — the next step is a technician, not another reset.

Resetting the Bryant furnace

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.

Frequently asked questions

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Facts on this page were checked against manufacturer documentation: shoredist.com · manuzoid.com · www.manualshelf.com · www.manualsdir.com · www.manualshelf.com · manualsdump.com · manualsdump.com · www.manualsdir.com · www.manualslib.com · manuals.plus