Rheem Furnace Error Codes List: Every Code Explained
Every Rheem furnace error code we could verify against Rheem's own documentation — what it means, what usually causes it, and the first fix to try — in one table. Codes differ between model series, so treat your model's tech sheet as the final word.
How to read and retrieve error codes on Rheem furnaces
Generation decides the diagnostic path. On the single-display controls (R95P, (-)801S/(-)801P) a two-digit fault is shown one digit at a time — first digit for one second, second digit for one second, then a half-second pause — repeating until the fault clears, and each fault is shown a minimum of two times. Those boards also recall history for free: on a power reset, the three most recent faults less than a week old are flashed in succession, most recent first; the fault buffer clears itself after one week and can be cleared manually with the SW4 dipswitch sequence in the manual. Communicating models (dual 7-segment display, (-)802V/(-)97V, R96V) add a pushbutton status menu on the control that steps through active faults, firing rate, airflow and the fault history (FL) — up to six faults stored within 168 powered hours — and the buffer is cleared by holding the pushbutton for 5 seconds or more while FL is active. On EcoNet systems the same faults also appear as text and alert codes at the thermostat.
The complete Rheem furnace error code list
| Code | Meaning | Most likely cause | First fix |
|---|---|---|---|
| 0 | Standby — not a fault: the display reads 0 when no fault is present and there is no thermostat call; the furnace is idle | Normal state between calls for heating, cooling or continuous fan | No repair needed. If a call is active and the display stays at 0, have the thermostat and power supply checked — that check is technician work |
| 10 | One-hour lockout (soft lockout) — gas heating is shut down for one hour; the display alternates 10 with the causing code (11, 13, 14, 59, 61 or 93) | Four failed ignitions, five flame losses in one heat call, an unexpected flame, a dead blower, repeated water-sensed events, or an active 93 | Fix the paired code first. Auto-resets after one hour, or clears immediately by cycling power (soft lockout only: cycle the heat call off for 2–20 seconds) |
| 11 | Failed ignition — the furnace control ran an ignition attempt and flame was not established and proved; the code is displayed after the first failed attempt and stays until ignition succeeds or the failures escalate to lockout. | Flame sense rod unable to sense flame (Rheem's #1 listed cause) | Owner step, once only: with the gas confirmed on and no gas smell, cycle power to the furnace off and back on and let it make ONE full set of attempts. A furnace that lights and holds has cleared a transient; a furnace that returns to 11 has given you its answer — do not keep power-cycling it into repeated lockouts. |
| 12 | Low flame sense — the flame sense current from the flame rod is weak or marginal; Rheem classes this non-critical and heating continues normally | Most often the rod needs cleaning or is not properly connected (or its wiring is shorted/open); also an improperly mounted or poorly grounded sensor | Clean or replace the rod and check connections and furnace ground — Rheem assigns sensor cleaning to a qualified installer/service agency. Left alone, 12 escalates to 13 or 11 |
| 13 | Flame lost — after a successful ignition the flame was properly sensed and then was no longer sensed, while a valid heat call is still present | The code 12 flame-rod family (rod needs cleaning, poor connection or ground), or an unstable flame pattern | Clean/replace the rod, check wiring and ground; a technician checks burner fit and door gasket/seals for the unstable-flame branch. Five losses in one heat call escalate to 10 + 13 |
| 14 | Unexpected flame — flame is sensed while the gas valve is supposed to be off. Rheem calls this extremely critical; the furnace will not operate | Field miswiring of 24VAC to the gas valve solenoid, a gas valve stuck open, or a faulty control sensing flame that is not there | Do not run the furnace; a one-hour lockout (10 + 14) follows once it clears. Wiring correction and gas valve/control replacement are licensed technician work |
| 20 | Twinning fault — on a twinned pair (two furnaces, common duct system and thermostat, linked by the TWIN terminal), twinning was detected and then lost in the same power cycle | A broken, disconnected or miswired twin link — Rheem's twinning section states the control declares 20 when a detected twin link is lost mid-cycle | Confirm the C, W and TWIN wiring between both controls (identical boards, same phase) — technician work. A single, non-twinned furnace should never show 20 |
| 22 | Main limit open — the main limit control (on (-)801S models, main limit or HALC) is open; open over 150 seconds during a heat call, the display alternates 61 and 22 | Over-temperature protection tripped; Rheem reads a limit open over 150 seconds as a dead-blower event — the blower should be carrying the heat away | Let it cool and re-close; never bypass the limit. A repeating 22, or 22 with 61, is technician blower/airflow diagnosis |
| 26 | Line and neutral reversed — the line-voltage polarity at the control is wrong (the communicating manuals add 'or poor ground') | L1 and neutral swapped at the furnace control or junction box, or an inadequate furnace ground; Rheem's ignition troubleshooting also lists swapped L1/neutral as a no-light cause | Correcting line polarity and grounding is licensed electrician/HVAC technician work. Do not swap wires by trial — polarity faults also corrupt flame sensing |
| 30 | Open fuse (communicating models) — the control's low-voltage fuse has opened; the furnace will not operate in any mode | An electrical short from the low-voltage (24VAC) side to ground or common | A technician repairs the short circuit condition and only then replaces the fuse; a fuse replaced into a live short just opens again |
| 33 | MRLC open — the Manual Reset Limit Control (aka roll-out switch) has opened: flame rolled out into the burner compartment. Rheem says this should rarely if ever be seen and indicates a very serious problem | Insufficient venting (inlet or exhaust), loose or faulty wiring, or an unstable flame pattern | Do NOT just reset it and run. A technician must first check vent obstructions/lengths, pressure switches (not welded/bypassed), inducer speed, seals and heat-exchanger damage — then reset it manually |
| 44 | Low pressure switch closed, inducer off (communicating models) — closed when it should be open, before prepurge; both switches closed in the proving period displays 44 and 55 alternately | A faulty switch, a switch physically bypassed in the field, loose/faulty wiring, or abnormal negative pressure on the vent without the inducer running | Never bypass a pressure switch. A technician replaces the switch, removes any bypass (and its reason), and checks venting/terminations |
| 45 | Low pressure switch open, inducer on high speed (communicating models) — the low switch has not closed at prepurge speed, so ignition cannot begin; the inducer runs five minutes, then retries indefinitely | Blocked/improperly terminated vent, vent length/elbows over maximum, faulty/disconnected inducer, faulty control (inducer relay), loose wiring, damaged hoses, wind gusts, or a faulty switch | Clear the vent/intake terminations and check the hoses; inducer/relay/switch diagnosis is technician work — never jumper the switch |
| 46 | Low pressure switch open, inducer on low speed (communicating models) — seen only after heat is established and the furnace switched to low fire: the low switch drops out and the gas valve is de-energised | Code 45's vent-path family: blockage/improper termination, excess vent length/elbows, inducer/control faults, loose wiring, damaged hoses, wind gusts, faulty switch, missing high-altitude kit | Clear the vent path and hoses first; proving draft on high fire but losing it on low fire needs a technician's draft measurement, not a guessed switch |
| 55 | Pressure switch stuck closed when it should be open — still closed before the inducer runs (communicating multi-switch models: the HIGH switch, inducer off; both switches closed shows 44 and 55 alternately) | A faulty (welded) switch, a switch physically bypassed in the field, loose/faulty wiring, or abnormal negative pressure in the vent with the inducer off | Never bypass a pressure switch. A technician replaces a welded switch, removes any bypass (and its reason), and checks venting/terminations |
| 57 | Pressure switch stuck open when it should be closed — it will not close with the inducer running, so ignition cannot begin (communicating models: the HIGH switch open, inducer on high speed; the furnace may drop to low fire if the low switch stays closed) | Blocked/improperly terminated vent, vent length/elbows over maximum, faulty/disconnected inducer, damaged switch hoses, wind gusts, or a faulty switch | Clear the outdoor vent/intake terminations and check the hoses; switch and draft measurement are technician work — never jumper the switch |
| 58 | Water sense circuit open (condensing models) — the control cannot detect continuity to the collector-box water sensors; no gas heating, other modes run normally | Damaged control-to-sensor wiring, a bad P4 connection, or a sensor removed — Ruud's portal notes this is a deliberate alert that the circuit was disconnected/tampered with | A technician repairs wiring/connections or replaces the sensor. Do not defeat this circuit — it refuses operation when the condensate safety is disconnected, by design |
| 59 | Water sensed (condensing models) — water backed up in the collector box and the sensor detected it (present continuously at least 10 seconds); heating shuts down, repeated events bring up lockout 10 + 59 | A blocked condensate drain or drain trap, damaged sensor wiring touching sheet metal, or a sensor removed from the collector box with its probe touching sheet metal | Clear the drain/trap blockage — the owner-safe fix for most 59s. Wiring/sensor faults are technician work. EcoNet shows this as alert A059_F/T059_F |
| 60 | Blower fault — blower can still run (communicating models). Non-critical: operation continues, but the blower runs at less-than-optimal conditions | The blower has hit its maximum speed or torque limit, or its temperature limit, because static pressure is too high | Reduce static pressure: clean/replace the filter, remove the duct obstruction or repair the duct — Rheem's stated solution for this code |
| 61 | Blower fault — blower unable to run. Critical: no operation in any mode. Rheem also declares 61 when the main limit has been open over 150 seconds during a heat call (the display then alternates 61 and 22): the control reads a limit that cannot re-close as a dead blower, because the blower should be carrying the heat away. A fourth dead-blower declaration in one heat call enters hard lockout. | Motor thermal-limit trip — restriction or bearing failure | Obstruction branch: with power off, a technician removes whatever blocks the wheel, confirms the wheel is undamaged and tight on its shaft (setscrew proven, not assumed), and retries the motor once. Per the (-)97V manual, a motor that still fails after the obstruction is removed may be permanently damaged and is replaced. |
| 66 | Blower cutback (communicating models) — Rheem states this is an operating indicator, not a fault: the motor is at the highest RPM/torque its specification allows, but the application asks for more to deliver the desired airflow | Excessive static pressure — improperly designed or restricted ductwork, or a filter needing cleaning or replacing | Treat 66 as an airflow warning: service the filter and have the duct restriction corrected; the furnace keeps running |
| 68 | No blower communications (communicating models) — the control (I.F.C.) cannot communicate with the blower motor. Critical: no operation in any mode | Control-to-motor wires disconnected or poorly connected, no line voltage to the motor, faulty/corrupted model data, or catastrophic motor failure | A technician checks motor wiring and line-voltage wiring to the PFC choke and ECM motor, replaces the model data card (correct ProStock part) if corrupt, or replaces the motor |
| 93 | Internal control fault — a severe fault in the control itself; no operation in any mode, and the (-)801S manual classes 93 as a hard lockout (not resettable by cycling the heat call) | An internal microprocessor fault on the control (I.F.C.), or voltage on the gas valve solenoid circuit when there should be none (incl. a welded relay) | A technician checks for gas-valve-circuit miswiring, then replaces the control if the board failed. During a soft lockout, 93 alternates with 10 |
| C | Compressor on — an operating display, not a fault: cooling or heat-pump heat operation (communicating models show lower-case 'c' for low-stage cooling) | A normal call for cooling or heat-pump heat is in progress | No repair needed; during a lockout the control may show the lockout code instead of C even while answering a cooling call |
| F | Continuous fan on — an operating display, not a fault: the blower is running on a continuous-fan call from the thermostat | The thermostat's fan setting is calling for continuous blower operation | No repair needed. If the blower runs when it should not, check the thermostat fan setting first |
| H | Gas heat on — an operating display, not a fault (on communicating models a lower-case 'h' means the thermostat is requesting low-stage heat and 'H' high-stage heat) | A normal call for gas heating is in progress | No repair needed. If 'h' alternates with fault 57, the furnace is running on low fire because the high pressure switch is open — see code 57 |
| d1 | No model data (communicating models) — without it the furnace cannot function in any mode, including thermostat calls | Typically the model data (memory) card is missing — lost/disconnected, or not transferred when the control was replaced (Rheem requires it be saved and fitted to the new control) | A technician refits the original card in connector P6, or orders the correct replacement for the exact model from ProStock, then cycles power. Never use another furnace's card |
How to reset / clear error codes on Rheem furnaces
Rheem fault codes are shown as two-digit codes on the control's 7-segment display and clear once the fault condition is gone. Lockouts follow Rheem's documented rules: soft lockouts (the one-hour lockout, code 10, and the five-minute lockout when the low pressure switch fails to close after 60 seconds of inducer operation) auto-reset when their timer expires, and any lockout can be cleared immediately — once the original fault is cleared — by cycling power to the unit off and back on, or, for soft lockouts only, by cycling the heat call off for more than 2 seconds but less than 20 seconds. Hard lockouts are the exception: code 93 cannot be reset by cycling the heat call, and a dead-blower hard lockout (code 61, declared four times in one heat call) needs the repair plus a manual reset of power. Clearing a lockout without fixing its cause just restarts the count to the next one.
How to diagnose any Rheem furnace code
Work the problem in this order — and stop at any point where gas, combustion or mains wiring is involved, because those belong to a licensed HVAC technician: (1) record the code exactly: count LED flashes slowly, twice, or photograph the alphanumeric display; (2) check the free things homeowners legitimately own: the thermostat is calling for heat, the furnace power switch and breaker are on, the filter is not clogged solid (a starved furnace overheats and locks out on limit codes), all vents and the return are open, and the condensate drain is not blocked on condensing models; (3) reset once — at the power switch, off for 30 seconds — then watch a full call for heat from the beginning: inducer, ignition, flame, blower, in that order; where the sequence stops is the fault family the code names; (4) a code that returns immediately is an active fault — do not keep resetting a lockout, especially any flame or limit code; (5) everything inside the burner compartment — flame sensor cleaning is the one grey area many manuals allow owners, but gas valves, burners, heat exchangers and control boards are professional work. If you smell gas at any point, leave and call the gas utility, not a helpline.
How Rheem's 7-segment two-digit display works — and why the internet's Rheem 'flash tables' contradict it
Modern Rheem (and Ruud) furnaces do not blink fault codes at all: the Integrated Furnace Control carries a 7-segment LED display that shows the fault as digits. In standby with no call and no fault it reads '0'; during normal operation it shows a letter — 'H' for gas heat, 'C' for compressor (cooling or heat-pump heat), 'F' for continuous fan (communicating models use lower-case letters for low-stage calls, 'h', 'c'). A two-digit fault on the single-display controls (R95P, (-)801S/(-)801P) is shown sequentially: the first digit for one second, the second digit for one second, then a half-second pause, repeating until the fault clears — and every fault is displayed at least twice, even if it clears sooner. When two faults belong together, both are shown alternately with the display's top segment lit for half a second between them, which is why a furnace in ignition lockout appears to 'flash' 11, then 10, then 11: those are two complete codes taking turns, not one code changing its mind. Communicating models (R96V/*96V, (-)802V, (-)97V) use a dual 7-segment display plus a pushbutton status menu and an EcoNet thermostat that spells the fault out in words. The older generation is genuinely different hardware: RGRM/RGTM-era boards have four separate LEDs labelled FLAME, STATUS, POWER and CFM, and the STATUS LED really does blink — but Rheem's own table for it is short and specific: steady on is normal, 1 blink is ignition failure/1-hour lockout, 2 blinks pressure switch stuck open, 3 blinks limit switch open, 4 blinks pressure switch stuck closed, 5 blinks is explicitly 'Not applicable', and 6 blinks is line and neutral reversed — while the CFM LED blinks out the target airflow in hundreds of CFM, a count owners routinely mistake for a fault pattern. The contradictory 'Rheem flash tables' online are what happens when those three systems are collapsed into one list and padded with other brands' charts: Carrier-style 1-to-9 flash assignments get relabelled as Rheem, the RGRM six-blink list gets stretched to nine entries, a '5 flashes = twinning' claim circulates for boards whose own manual says 5 blinks is not applicable (on the display generation, twinning is code 20), and genuine 7-segment codes get described as flash counts. The practical rule: identify the display first. Digits on a 7-segment display are read with the two-digit chart; blinks on a four-LED board are read with that board's own short table; and the chart printed for your exact model outranks every generic list — including, where they differ, this one.
Ruud is the same furnace family: shared manuals, shared chart, and the EcoNet alert path
Rheem and Ruud furnaces are one platform sold under two badges, and Rheem's own documentation is written that way: the installation manuals for this generation are titled with a placeholder — '(-)801S', '(-)802V', '(-)97V' — because the same book covers both brands' versions of the series, with the brand letter filled in on the model number (Rheem models carry an R prefix, Ruud's a U: R96V beside U96V, R97V beside U97V, the (-)-series downflow and upflow models likewise). The fault system is shared, not merely similar: the same 7-segment control, the same two-digit chart (0 standby, H/C/F operating letters, 10 through 93), the same lockout arithmetic, and the same fault-recall behaviour appear in the documentation for both badges, and Ruud's own technical portal publishes the platform's water-management circuit with the same IFC codes — water sensed is fault 59 on the two 7-segment LEDs, water circuit open is fault 58 — in the same words as Rheem's. A Ruud owner can therefore use the Rheem chart on this page, and a Rheem owner can use a Ruud manual for the same series, provided the generation matches: a Ruud with a four-LED board follows the LED table, not the digit chart, exactly as a Rheem does. The one reporting path that sits on top of the shared chart is EcoNet. On communicating models the furnace still stores and displays the two-digit code at the control, but the EcoNet thermostat also reports the fault in its own format: plain-language fault text on its active-fault screen, and alert codes of the A/T form — Ruud's portal documents A058_F (water circuit open) and T059_F/A059_F (water sensed) for the same events the board shows as 58 and 59. EcoNet also changes what the homeowner sees: Rheem does not display a failed ignition (11) or a flame loss (13) to the homeowner unless it has happened at least three times within a single heat call, although the thermostat's active-fault screen shows it from the first occurrence and the board logs it once per heat call. So on an EcoNet system, 'the thermostat showed nothing' does not mean the furnace never faulted — read the board display and the active-fault screen before concluding anything, and when you call a technician, quote the two-digit board code together with the full model number, whichever badge is on the door.
Blink codes, display codes and lockouts
Two generations of fault reporting live side by side on modern furnaces. Older and simpler boards report through a single LED: a repeating count of flashes, read slowly against the chart printed inside the blower door — that chart, for your exact model, outranks any list on the internet, including this one. Newer communicating furnaces show alphanumeric codes (the E-series in the table above) and store a fault history a technician can scroll. Both generations share the lockout idea: after a set number of failed attempts at the same step — ignition is the classic — the board stops trying for a period (often an hour, or until power is cycled) instead of cycling forever against a fault that could overheat or flood the burners with unburned gas. A furnace in lockout is not broken by the lockout itself; it is a furnace that has already failed the same step repeatedly and is waiting for someone to find out why.
Furnace codes are also seasonal in a way washer codes are not. The first cold snap produces a wave of ignition and flame codes from furnaces that sat idle all summer — oxidised flame sensors, spider-nested burners, pressure-switch hoses holding condensate from the cooling season. Deep-winter adds frozen condensate lines on high-efficiency models and intake/exhaust terminations blocked by snow or ice, which present as pressure-switch codes. A code that appears once, on the coldest night of the year, and never again has often met its cause already; a code that appears every cycle, in any weather, is a component asking to be tested.
The most searched Rheem furnace codes, in detail
11 — Failed ignition
Code 11 is Rheem's ignition-failure report on the 7-segment control generation, and Rheem's own ordering of causes surprises most owners: the first cause the (-)97V manual lists is not a dead igniter but the flame sense rod being unable to sense flame — the burners may light and the control still declares a failed ignition because it never saw proof of flame. The sequence around the code is fixed: after a failed attempt the inducer completes a 20-second postpurge and the control tries again, up to four consecutive attempts. Four in a row elevates the fault to the one-hour lockout, and the display then alternates '11' with '10'. On communicating (EcoNet) systems Rheem hides the first one or two failures from the homeowner display — 11 is only shown to the homeowner after at least three failures in a single heat call — but it appears in the thermostat's active-fault screen from the first failure, and it is logged into the fault buffer only once per heat call.
Most likely cause: Flame sense rod unable to sense flame (Rheem's #1 listed cause) — The rod may need cleaning or may not be properly connected. The burner can light perfectly and still produce an 11 if the rod is coated, mispositioned or its wiring to the control is open — the control never receives proof of flame inside its trial window, so it shuts the gas valve and records a failed ignition.
First check: SAFETY: this is a gas appliance failing to light. If you smell gas at any point, stop — no more start attempts — and call the gas utility or a licensed HVAC technician. Never open the gas train, jumper a pressure switch or limit, or hold a gas valve open manually to 'help' it light.
If it keeps coming back: An 11 that returns after the rod is cleaned and the gas proven is climbing Rheem's own cause list in order: igniter spark position degrading, carry-over worsening as burners corrode, manifold pressure sagging (a supply/regulator story that often appears only on the coldest nights when every appliance runs), or polarity/ground problems after electrical work. An 11 that arrives only on the first call after long idle periods, then runs for weeks, fits a supply or sticky-valve pattern — describe that timing to the technician; it is worth more than the code.
61 — Blower fault
Code 61 is Rheem's verdict that the circulating blower — the motor that moves house air over the heat exchanger and through the ducts — cannot run, and it is one of the few Rheem codes that stops everything: the SHORT chart's wording is 'no operation in any mode', so cooling and continuous-fan calls are refused alongside heating. The code reaches that verdict by two different roads. The direct road is the motor reporting itself: on communicating models the (-)97V manual's blower-diagnosis section describes an internal-error case in which the motor can still communicate with the furnace control but is experiencing an internal problem such as overheating, and the control displays 61 — with the manual's sobering pair of notes that an internal overload may reset once the condition causing it is removed, but the motor will likely need to be replaced. The same section gives the locked-rotor version: if the blower wheel is blocked by an obstruction, the motor sits in locked-rotor state and the control reports 61; remove the obstruction and try again, and a motor that still fails may be permanently damaged. The indirect road runs through the limit circuit, and the *96V lockout section times it exactly: the control declares the blower inoperable (dead) if the main limit control has been open for more than 150 seconds — gas heating is terminated, but the control keeps trying to operate heating for up to four attempts in case the blower starts working again, and if a dead blower has been declared four times in one heat call, the control enters hard lockout with 61 set and displayed. That is why a 61 can arrive on a furnace whose motor is mechanically fine but electrically silent, and also on one whose motor is healthy but was never told to run: from the heat exchanger's side of the cabinet, both stories are the same emergency — heat being made with no air to carry it. Read 61 alongside its neighbours before condemning anything: 60 is the communicating models' non-critical version (blower can still run, at less-than-optimal conditions, because static pressure is too high), 66 is not a fault at all but an operating indicator that the motor is at its RPM/torque limit, and 68 is the communications failure (control cannot talk to the motor). A 61 is the end of that scale: the blower is not struggling or unreachable — it is unable to run.
Most likely cause: Motor thermal-limit trip — restriction or bearing failure — First in the verified cause list: the motor's own thermal protection opens because the motor is working against a restriction (a loaded filter or choked duct system driving static pressure up) or because its bearings are failing and friction is doing the heating. A motor that trips thermally, cools, runs briefly and trips again is telling this story in instalments.
First check: SAFETY: this code stops every mode for a reason — the furnace cannot move air. Never run heating with a blower that will not run, and never bypass the limit circuit to 'test' it: a limit open past 150 seconds is how this code is declared. Power OFF at the furnace switch before opening panels. Gas smell, scorch marks or a CO alarm: furnace off, licensed technician (gas utility for a gas smell).
If it keeps coming back: A 61 that returns after an obstruction is cleared and a filter changed is a motor in decline: bearings adding friction week by week, a thermal protector weakening toward earlier trips, or an internal fault the communicating manual expects to end in replacement. A 61 that returns only on the coldest nights is load confessing — longest runs, highest static pressure, a marginal duct system — while a 61 that returns immediately after board work is the model-data card until proven otherwise. Each dead-blower declaration is also a limit event: heat made with no air to carry it is thermal stress on the heat exchanger, so a furnace cycling through 61s is spending exchanger life as well as comfort.
Less common and model-specific codes
Search data shows owners also meet these codes on Rheem furnaces: 23, 34, 65, 67, 71, 77. They are not part of the core code list Rheem publishes for most models — several are series-specific, abbreviated display readings, or codes carried over from a sister platform — so we do not publish meanings for them rather than guess. Treat them by symptom: note what the machine was doing when the code appeared (filling, draining, heating, spinning), run one full power cycle (5 minutes off), and if the code returns, match the symptom to the closest documented family in the table above and check the tech sheet stored inside your machine for the model-specific definition.
Deep-dive guides for the most searched codes
Related guides
Facts on this page were checked against manufacturer documentation: pts.myrheem.com · www.manualslib.com · pts.myrheem.com · pts.myrheem.com · www.manualslib.com · my.ruud.com:443