How to Reset York Furnace Error Codes

Resetting a York furnace is generation-aware work: the tri-colour controls store up to five fault codes through a power cut, clear their soft lockouts (6, 7 and 8 red flashes) on a 60-minute watchdog, and keep their hard lockouts — the 11-flash blower lockout and the standard boards' rollout fault — waiting for a human, a repair and a power cycle. This guide covers reading the stored history with the LAST ERROR button before anything is cleared, each lockout's documented exit, the manual-reset roll-out switch that answers to no timer, and the faults for which a reset is pointless because the condition is still standing in the furnace.

Two generations, one LED: read the reset rules for the board you have

York's residential furnaces report through one tri-colour LED on two generations of control, and the generations share more reset behaviour than code meanings — which makes the differences easy to miss and worth stating first. Shared: both generations store up to five fault codes in memory, retained even if power is lost; both use the LAST ERROR button for retrieval and clearing; both run the one-hour soft-lockout family; and both contain manual-reset roll-out hardware that no control reset reaches. Different: the generations disagree on real code meanings (red 6 is a pressure-switch recycling lockout on standard boards and a modulating gas valve failure on modulating boards; red 10 likewise splits; red 12 exists only on modulating boards, as the ID-plug report), so a reset performed against the wrong generation's chart can 'clear' a code you have misread entirely. The door chart discipline that governs all York code work governs resets too: the diagnostic chart printed inside your own blower door is the authority for your furnace, and the generation is a model question — conventional single-stage families (TG9S, TMLX, GF9S/GY9S in the manuals checked) speak the standard language, modulating families (TP9C, CM8M/YM8M) speak the modulating one. Two further framing facts organise everything below. A York fault code is one of two species: a condition report, which ends when its condition ends (a limit re-closes on cooling; a pressure switch proves on a clean start), and a lockout, which is a timed or latched state the control entered by counting events (three failed ignitions, five flame losses, a limit open past five minutes). Resets apply to lockouts; condition reports are 'reset' only by fixing the condition, a distinction the sections below keep sharp. And the stored history is evidence with a delete key — York reserves its retrieval for a qualified service technician — so the order of operations on any York reset is: read, record, fix, then clear.

Condition reports are not lockouts: what ends by itself, and how

Most York codes an owner meets are condition reports, and their 'reset' is the condition's cure plus an ordinary restart. Four red flashes (limit switch open) ends as the furnace cools and the limit re-closes — the control runs the blower and inducer during the condition precisely to bring that cooling about — provided the airflow cause (filter, registers, blower) has been addressed; a power cycle adds nothing to the physics. Three red flashes (pressure switch stuck open) ends when the switch closes on a normal start sequence after the vent, intake, condensate or hose obstruction is cleared: cycle the thermostat off and back on, or cycle power, and a furnace that proves draft proceeds to ignition as if the report had never been filed. Two red flashes (switch stuck closed) ends when the switch circuit honestly reads open at the next start check — which is to say, after the switch, wiring or transducer repair, never before it. The steady states frame the same lesson from the other side: a steady red (control fault) does not clear by waiting, and an LED off (no 24V power to the board) is a supply check — breaker, furnace switch, door seating, board fuse — not a reset opportunity. The practical test for species is a single question: is the reported condition still physically true? If yes, every reset in this guide will re-report it, because the control is measuring, not punishing. If no — the obstruction is cleared, the limit has cooled, the switch is honest — then an ordinary restart is the whole procedure, and a code that survives its condition's proven cure has changed species in front of you: it is now a control or sensor diagnosis, and it belongs to a technician with the history you recorded before touching anything.

Soft lockouts and the 60-minute watchdog: faults 6, 7 and 8

York's soft lockouts are the counted faults the control is willing to forgive on a timer, and the standard boards' manuals document the mechanism under its own name: a 60-minute automatic reset from lockout — a 'watchdog' circuit that resets the lockout condition after 60 minutes. The faults it covers are named exactly: operational faults 6, 7 and 8 will be reset. On standard boards those are: 6 red flashes (the pressure switch opened 4 times during one call for heat, then a one-hour lockout), 7 red flashes (ignition lockout — flame could not be established in three tries), and 8 red flashes (flame lost five times — four recycles — during a single heating cycle). The watchdog's stated purpose deserves quoting in spirit: it provides protection to an unoccupied structure if a temporary condition caused the malfunction — the manuals' own example is low incoming gas supply pressure preventing operation, with heat restored at some point after the pressure returns. In other words, the hourly retry exists for faults whose causes can heal without hands: a supply restored, a gust pattern passed, a marginal vent condition eased. During the hour the furnace will not retry on thermostat demand; after it, the control tries again on its own. A power cycle after a genuine fix is the legitimate manual shortcut to the same exit — fix first, cycle once, judge by a full cycle — while power-cycling to skip the hour without a fix merely spends the next set of counted events sooner. One generation caution belongs here: on modulating boards, 7 and 8 carry the same ignition meanings and the same one-hour behaviour (the TP9C text states the lockout and hourly retry for both), but 6 means the modulating gas valve, not a pressure-switch count — so the '6, 7, 8' watchdog trio, as a trio, is standard-board documentation, and a modulating owner should read their 6 against their own door chart rather than this section's first sentence.

Hard lockouts: the repair, then the power cycle — in that order

York's hard lockouts are the counted faults the control refuses to forgive on any timer, and their exit procedure is uniform: fix the cause, then cycle power off and on at the furnace switch. The documented exemplar is 11 red flashes: a limit switch opened and stayed open for more than five minutes, on which the control assumes the blower has failed and enters hard lockout. No hour of waiting clears it, because its cause — a blower motor or wheel that has stopped moving air — does not heal while a house waits; the blower repair comes first, the power cycle second, and a cycle performed first simply re-enters the same five-minute countdown toward the same lockout. The standard boards' roll-out fault belongs to this family in spirit and exceeds it in kind (the next section): a tripped roll-out is a hard lockout whose reset lives at the switch itself, not at the breaker. The discipline that separates a hard-lockout reset from superstition is verification: after the repair and the single power cycle, the furnace must complete the full operation that used to kill it — for 11, a long heating run with the blower moving air and the limit staying closed — before the job is called done. A hard lockout that re-forms after an honest repair is new information about the repair's branch (the blower was not the whole story; the limit's five minutes were bought by something upstream of it), and it should be handed to a technician with that history intact — which is one more reason the stored codes are read and recorded before the first power cycle, even though York's memory, mercifully, survives the cycling that erases other brands' histories.

The roll-out switch: a reset that lives at the device, after its cause

One York reset is not electrical at all. The roll-out switch — on the burner assembly, a manual-reset device with a small button in its centre — opens when flame rolls out of the burner compartment (5 red flashes: on standard boards, the roll-out switch only; on modulating boards, roll-out or the auxiliary limit / condensate pressure switch sharing the count). York's manuals state the reset and its precondition together: push the button in the centre of the switch to reset it — and check for proper combustion air, proper inducer operation, and primary heat exchanger failure or a burner problem, because the switch must be reset only after correcting the failure condition. The standard generation adds the lockout consequence: a roll-out fault also enters hard lockout, so the sequence is cause corrected, switch reset by hand, then power cycled — skipping any step strands the others. The safety framing is identical to every other brand's on this site because the physics is identical: roll-out means flame visited a compartment built on the promise that it never would, and its causes (starved combustion air, a failing inducer, a breached exchanger, a burner fault) are still present at any temperature and through any number of breaker cycles. A household's correct actions on a tripped York roll-out are therefore: furnace off, compartment closed, switch unpressed, technician called. If the switch cannot be reset, or trips again after a correct repair, the modulating manual's instruction is the standing one: contact a qualified serviceman — a second roll-out is a stop-work event, not a second chance at the button. No section of this guide should be read as softening that: of all York resets, the roll-out's is the one where the reset is deliberately the last and least important step.

Reading stored fault history: the LAST ERROR button, before anything is cleared

York's controls remember, and the memory has rules that a reset can destroy if it is performed in the wrong order. The documented system, identical in structure on both generations: the control stores up to five separate error codes — if more occur, only the five most recent are retained — and the memory is retained even if power to the furnace is lost. Retrieval is by the board's LAST ERROR button, a feature York states should only be used by a qualified service technician, and it works only with no active thermostat signals: any call for heating, cooling or continuous fan must be ended first. Press the button and the LED flashes the stored codes in memory, most recent first, with a two-second pause between each code; after all have been displayed, the LED resumes the normal slow green flash after a five-second pause, and pressing again repeats the series. Two answers are not faults: if there are no error codes in memory, the LED flashes two green flashes; and clearing is deliberate — hold the LAST ERROR button for more than five seconds and the LED flashes three green flashes when the memory has been cleared, then resumes slow green. The owner's stake in this technician feature is timing, not operation: a power cycle does NOT erase this memory (it survives power loss by design), so York owners are spared the read-before-you-cycle emergency of some other brands — but a cleared history is unrecoverable, and the five-code stack is often the whole diagnosis of an intermittent fault: the 2 that began appearing after the 3s stopped, the 7s stacking weekly behind a 'mystery' no-heat, the single 11 at the bottom of a season of 4s. Record the stack — codes in order, with dates and weather where you know them — before any service visit clears it, and tell the technician what it said. Clearing memory to 'start fresh' before the pattern is read is the one York reset that destroys value instead of restoring heat.

When a reset is pointless: standing conditions that will simply re-report

A reset is a question — has the condition changed? — and on a family of York faults the answer is known in advance, making the reset pointless rather than merely premature. The active limit family leads it: a 4-flash limit still open will re-open or stay open through any restart while its airflow cause stands, and an 11-flash hard lockout power-cycled without blower work re-enters its own five-minute proof and locks out again on schedule. An open roll-out (5 flashes) cannot be power-cycled into closure at all — its reset is a hand at the switch after an inspection that has not happened. Pressure proofs behave the same: a 3-flash vent obstruction still blocked re-fails its proving on the next start, and a 2-flash switch still welded re-fails its at-rest check before the inducer turns. The control-fault states close the list: a steady red (internal control failure; on modulating manuals, also shown when only one of the 115V/24V supplies reaches the board) answers a power cycle by returning if the board has failed, and an LED off (no 24V power to the board) is a supply fault to be found — breaker, switch, door, board fuse, transformer — not a state to be reset. Even the soft lockouts join the list conditionally: cycling power to skip a 7-flash hour without touching the ignition chain buys three more unproved gas-valve openings and a fresh hour. The common thread is measurement: York's control is not holding a grudge in any of these states, it is holding a reading. The correct response to a pointless-reset fault is the condition's own fix list — worked from the code's own guide on this site — after which the reset sections above become short again: condition cured, ordinary restart, full-cycle verdict.

Reset discipline: fix, reset once, verify by a full cycle — and keep the notebook

Collected, York's reset rules make a short discipline that fits both generations. Read first: the active code (colour and count, three full repetitions), then the stored stack if a technician visit is coming, with the door chart settling any generation doubt. Fix the named condition — filter and airflow for the limit family, terminations and condensate for the pressure family, supply facts for the ignition family — because every legitimate York reset is the second step of a repair, never the first step of a hope. Reset by the state's own exit: nothing for a cured condition report beyond an ordinary restart; the hour (or one power cycle after the fix) for soft lockouts 6, 7 and 8; repair-then-power-cycle for hard lockouts; hand-at-the-switch, after inspection, for the roll-out. Then verify by the operation that used to fail — a long heat run for a limit, a cold start for a pressure proof, three clean lights' worth of confidence for an ignition chain — and let that full cycle, not the cleared LED, be the verdict. Two habits protect the future. The notebook: code, date, outdoor temperature, what the furnace was doing, what you changed — York's memory holds five codes, but your notebook holds the season, and intermittent faults confess to notebooks. And the escalation rule: the same code twice in a heating season after honest fixes is a diagnosis appointment, not a reset routine — a household that knows its furnace's lockout schedule by heart is operating a fault as a feature. York built the watchdog for the empty house and the LAST ERROR button for the technician; the owner's reset craft is knowing which of the two your situation actually calls for, and refusing to let a button substitute for the fix the code already named.

Key takeaways

• Read the stack before clearing anything: York stores five codes through a power cut and plays them back most-recent-first via LAST ERROR (two green flashes = empty; hold over five seconds = cleared, confirmed by three green) — that stack is the diagnosis of every intermittent fault.
• Learn your lockout's species: soft lockouts (standard-board 6, 7, 8) retry on the 60-minute watchdog; hard lockouts (11, and the roll-out fault) wait for a repair and a power cycle; condition reports like 3 and 4 flashes end only when their condition does.
• A tripped roll-out switch is reset by hand at the switch — and only after its cause (combustion air, inducer, heat exchanger, burner) is corrected. No power cycle reaches it, and a second trip is a stop-work event.

Resetting the York furnace

York tri-colour controls store up to five fault codes in memory, retained even if power is lost. Soft lockouts (on standard boards, the 6, 7 and 8 red-flash faults) reset automatically after one hour — the control keeps retrying hourly and resumes if the temporary condition, such as a gas-supply interruption, has cleared. Hard lockouts (for example the 11 red-flash blower-failure lockout, and the rollout fault on standard boards) do not restart on their own: fix the cause, then cycle power off and on at the furnace switch. A tripped rollout switch is a manual reset at the switch itself, and only after the rollout cause has been found. Clearing any lockout without fixing its cause just restarts the countdown to the next one.

Frequently asked questions

Related guides

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