Rheem Furnace Error Codes — Meanings, Causes & Repair in Greater Vancouver

Seeing a fault code on your Rheem furnace? This guide explains what the most common Rheem furnace error codes mean, what’s safe to check yourself, and when to call HeatLand’s licensed, TSBC-certified gas technicians for Rheem furnace repair across Metro Vancouver and the Fraser Valley.

The codes below apply across common Rheem models (Prestige, Classic Plus, Classic). Meanings follow Rheem’s documented fault codes — always confirm against your unit’s own manual, because exact wording can vary by model, control board and firmware.

How to read Rheem furnace error codes

Rheem/Ruud furnace diagnostic codes — newer models (Prestige/Classic Plus 80%-96% AFUE, e.g. R98/R97/R96/R95/801S/802S series) display a numeric code on a 7-segment LED; legacy models (Criterion II, Classic 90 Plus, Achiever) flash a STATUS LED a set number of times. Both schemes are listed below; the LED flashes a primary count, pauses, then repeats.

Rheem furnace error codes & what they mean

These are the Rheem furnace codes our Greater Vancouver technicians see most. Anything marked pro repair involves gas, electrical, sealed-combustion or control-board work that must be done by a licensed gas technician (TSBC-certified in BC) — never open gas or electrical components yourself.

Code	What it usually means	Common causes	Safe to check yourself
0	Standby — no active fault; furnace idle and waiting for a call for heat from the thermostat DIY-checkable	Normal idle state — no fault present	Confirm the thermostat is set to HEAT and the setpoint is above room temperature
H	Gas heat ON — furnace is actively running a heating cycle DIY-checkable	Normal heating operation	No action needed — this indicates normal heating
C	Compressor ON — cooling or heat-pump heat call active (displayed when the furnace blower is energized for an outdoor unit) DIY-checkable	Normal cooling / heat-pump operation	No action needed — normal operation
F	Continuous fan ON — blower running in continuous-fan mode with no heat or cool call DIY-checkable	Thermostat fan set to ON rather than AUTO	If you want the blower to stop between cycles, set the thermostat fan switch to AUTO instead of ON
10	One-hour lockout — the control has locked the furnace out for one hour after repeated faults (typically repeated failed ignition or flame-related conditions). The furnace will retry automatically after the lockout, or can be reset by cycling power pro repair	Repeated ignition failures; Repeated loss of flame; Dirty flame sensor	Confirm the gas is on and other gas appliances work; Confirm the furnace switch and breaker are ON; Replace a dirty furnace filter
11	Failed ignition — the burners did not light (or flame was not sensed) within the allowed ignition trials pro repair	No gas / gas valve closed; Dirty or failed flame sensor; Cracked or failed hot-surface igniter	Confirm the gas supply is on and other gas appliances work; Replace a dirty filter; Confirm the thermostat is calling for heat
12	Low flame sense — a flame is present but the sensed flame current (microamps) is below the normal threshold pro repair	Dirty/oxidized flame sensor; Marginal flame-sensor position; Weak ground connection	Replace a dirty filter; Confirm furnace switch and breaker are ON
13	Flame lost — flame was established but then went out during the heating cycle pro repair	Dirty flame sensor; Low or fluctuating gas pressure; Failing gas valve	Confirm gas is on and other appliances work; Replace a dirty filter; Clear snow/debris from outdoor intake and exhaust vent terminals
14	Unexpected flame — the control senses flame when the gas valve should be closed (no call for flame) pro repair	Gas valve leaking through / not fully closing; Flame sensor reading residual flame; Faulty control board	Turn the furnace OFF at the furnace switch and call a licensed technician — a valve that does not fully close is a gas-safety concern
20	Twinning fault — error in the twinning circuit between two furnaces wired together (twinned), or twinning improperly configured pro repair	Incorrect twinning wiring; Twin-furnace communication error; Twinning enabled on a single (non-twinned) installation	No safe homeowner check — requires a technician familiar with the twinned-furnace setup
22	Main limit (or HALC, high-altitude limit control) open — the high-limit safety opened, usually from overheating / insufficient airflow across the heat exchanger pro repair	Dirty/clogged air filter; Closed or blocked supply/return registers; Failed blower motor or capacitor	Replace a dirty filter; Confirm supply and return vents/registers are open and unblocked; Confirm the furnace switch and breaker are ON
26	Line and neutral reversed — incoming 120 VAC line and neutral are wired backward (reversed polarity), or a grounding fault is present pro repair	Reversed line/neutral at the furnace or outlet; Missing or poor ground; Wiring error after recent electrical work	No safe homeowner check — line-voltage wiring must be corrected by a licensed technician or electrician
33	MRLC (Manual Reset Limit Control), also called the roll-out control, is open — indicates flame roll-out or excessive heat at the burner area pro repair	Flame roll-out from blocked/cracked heat exchanger; Blocked flue or venting; Failed inducer	Turn the furnace OFF at the furnace switch and call a licensed technician — flame roll-out is a safety hazard and the rollout control requires manual reset by a professional after the cause is corrected
45	Low-pressure switch open — the low (or single) pressure switch did not close, or opened, indicating inadequate venting/draft proving pro repair	Blocked or restricted intake or exhaust vent; Condensate drain blockage / water in the pressure tubing; Disconnected or cracked pressure-switch tubing	Clear snow, ice, leaves or debris from the outdoor intake and exhaust vent terminals; Replace a dirty filter; Power-cycle the furnace once
55	Pressure switch stuck closed when it should be open — the pressure switch reads closed before the inducer starts (it should be open at rest) pro repair	Pressure switch contacts stuck/welded closed; Wiring short across the pressure switch; Failed pressure switch	Power-cycle the furnace once; Confirm the furnace switch and breaker are ON
57	Pressure switch stuck open when it should be closed — the pressure switch did not close after the inducer started, so proper draft/venting could not be proven pro repair	Blocked or restricted intake/exhaust vent; Condensate or water in the pressure tubing or trap; Disconnected/kinked pressure-switch hose	Clear snow/ice/debris from the outdoor vent terminals; Replace a dirty filter; Power-cycle the furnace once
61	Blower fault — the blower is unable to run (the indoor blower motor failed to operate when commanded) pro repair	Failed blower (ECM/PSC) motor; Failed run capacitor (PSC models); Failed motor module	Confirm the furnace switch and breaker are ON; Power-cycle the furnace once
93	Internal control fault — the furnace control board detected an internal failure (e.g., welded relay or self-check failure); this is a hard-lockout condition pro repair	Failed integrated furnace control board; Welded relay on the control; Power surge / electrical damage	Power-cycle the furnace once to confirm the code persists; Confirm the furnace switch and breaker are ON
1 flash (STATUS LED)	Ignition failure — one-hour lockout. The control failed to establish/prove flame within the allowed trials and has locked out for one hour pro repair	No gas / gas off; Dirty or failed flame sensor; Cracked/failed hot-surface igniter	Confirm the gas is on and other gas appliances work; Confirm the furnace switch and breaker are ON; Replace a dirty filter
2 flashes (STATUS LED)	Pressure switch stuck open — the pressure switch will not close when the inducer is running, so venting/draft could not be proven pro repair	Blocked/restricted intake or exhaust vent; Condensate/water in pressure tubing; Disconnected pressure-switch hose	Clear snow/ice/debris from the outdoor vent terminals; Replace a dirty filter; Power-cycle the furnace once
3 flashes (STATUS LED)	Limit switch open — the main limit or roll-out control is open, typically from overheating / insufficient airflow (or flame roll-out) pro repair	Dirty/clogged air filter; Blocked supply/return registers; Failed blower motor or capacitor	Replace a dirty filter; Confirm supply and return vents/registers are open and unblocked; Power-cycle the furnace once
4 flashes (STATUS LED)	Pressure switch stuck closed — the pressure switch will not open (it is closed when it should be open, e.g., before the inducer starts) pro repair	Pressure switch contacts stuck/welded closed; Wiring short across the switch; Failed pressure switch	Confirm the furnace switch and breaker are ON; Power-cycle the furnace once
5 flashes (STATUS LED)	Twinning fault — fault in the twinning circuit between two furnaces wired together, or improper twinning configuration. (On some boards 5 flashes is listed as 'not applicable' / unused — meaning varies by model, so verify against the unit's wiring label.) pro repair	Incorrect twinning wiring; Twin-furnace communication error; Twinning configured on a non-twinned install	No safe homeowner check — requires a technician familiar with the twinned setup
6 flashes (STATUS LED)	Line and neutral reversed — incoming 120 VAC line and neutral are wired backward (reversed polarity) or a grounding fault is present pro repair	Reversed line/neutral at furnace or outlet; Missing/poor ground; Wiring error after electrical work	No safe homeowner check — line-voltage wiring must be corrected by a licensed technician or electrician
FLAME LED — OFF	No flame detected pro repair	No call for heat (normal when idle); Failed ignition; No gas	If the furnace is idle this is normal; If it occurs during a heat call, confirm gas is on and other appliances work, then power-cycle once
FLAME LED — rapid blink	Unexpected flame — flame sensed when none should be present (gas valve should be closed) pro repair	Gas valve not fully closing; Flame sensor reading residual flame; Faulty control	Turn the furnace OFF at the furnace switch and call a licensed technician — a valve not fully closing is a gas-safety concern
FLAME LED — slow blink	Marginal flame sense — flame current is weak / below the preferred range pro repair	Dirty/oxidized flame sensor; Marginal sensor position; Weak ground	Replace a dirty filter; Confirm the furnace switch and breaker are ON
FLAME LED — steady ON	Normal flame detected — flame proven within normal range DIY-checkable	Normal operation	No action needed — normal operation
POWER LED — OFF	No 24 VAC power to the control board pro repair	Furnace switch or breaker off; Blown low-voltage fuse on the board; Failed transformer	Confirm the furnace switch and breaker are ON; Confirm the blower-compartment door is fully closed (it presses a safety switch); Power-cycle the furnace once
POWER LED — ON	Control is powered (24 VAC present) DIY-checkable	Normal — control energized	No action needed — normal

Rheem furnace codes we get called for most

10 — One-hour lockout — the control has locked the furnace out for one hour after repeated faults (typically repeated failed ignition or flame-related conditions). The furnace will retry automatically after the lockout, or can be reset by cycling power

Typical causes include repeated ignition failures; repeated loss of flame; dirty flame sensor. A few things are safe to check yourself (Confirm the gas is on and other gas appliances work; Confirm the furnace switch and breaker are ON), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 10 on Rheem furnaces throughout Greater Vancouver.

13 — Flame lost — flame was established but then went out during the heating cycle

Typical causes include dirty flame sensor; low or fluctuating gas pressure; failing gas valve. A few things are safe to check yourself (Confirm gas is on and other appliances work; Replace a dirty filter), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 13 on Rheem furnaces throughout Greater Vancouver.

45 — Low-pressure switch open — the low (or single) pressure switch did not close, or opened, indicating inadequate venting/draft proving

Typical causes include blocked or restricted intake or exhaust vent; condensate drain blockage / water in the pressure tubing; disconnected or cracked pressure-switch tubing. A few things are safe to check yourself (Clear snow, ice, leaves or debris from the outdoor intake and exhaust vent terminals; Replace a dirty filter), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 45 on Rheem furnaces throughout Greater Vancouver.

22 — Main limit (or HALC, high-altitude limit control) open — the high-limit safety opened, usually from overheating / insufficient airflow across the heat exchanger

Typical causes include dirty/clogged air filter; closed or blocked supply/return registers; failed blower motor or capacitor. A few things are safe to check yourself (Replace a dirty filter; Confirm supply and return vents/registers are open and unblocked), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 22 on Rheem furnaces throughout Greater Vancouver.

Is it safe to keep running a Rheem furnace with a fault code?

Most Rheem fault codes put the furnace into a safe lockout for a reason. You can safely check the basics — the furnace switch and breaker on, a clean air filter, the gas supply on, the thermostat set to heat and calling, and — on high-efficiency models — the condensate drain not blocked or frozen — and restart it once. If the code returns, stop and book a technician. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911. A rollout or repeated limit trip can signal a heat-exchanger or venting problem — don’t keep resetting it.

Rheem furnace repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair Rheem furnaces — ignition and flame-sensor faults, pressure-switch and venting problems, limit and rollout trips, blower and igniter issues, and control-board errors — including units we didn’t install. We’re brand-agnostic, carry common parts, and give you an honest repair-or-replace assessment with upfront pricing and a free estimate. If your furnace is beyond economical repair, we’ll show you right-sized, high-efficiency replacement options and the rebates available.

Need it sorted fast? We offer priority emergency furnace repair. Explore Furnace services, browse all furnace error codes by brand, or request a free estimate.

Rheem furnace service areas

We repair Rheem furnaces across Greater Vancouver and the Fraser Valley, including:

Rheem furnace error code FAQs

Can I reset my Rheem furnace myself?

Yes — power-cycling the reset button once is generally safe after you’ve checked the basics (the furnace switch and breaker on, a clean air filter, the gas supply on, the thermostat set to heat and calling, and — on high-efficiency models — the condensate drain not blocked or frozen). If the furnace faults again right away, stop and note the code — repeatedly resetting a furnace that keeps locking out can mask a real problem. Call a licensed, TSBC-certified gas technician to diagnose it.

What does the Rheem C code mean?

On Rheem furnaces, C commonly indicates compressor on — cooling or heat-pump heat call active (displayed when the furnace blower is energized for an outdoor unit). Confirm the exact meaning against your unit’s manual — codes can vary by model and series — and have the repair done by a licensed, TSBC-certified gas technician. HeatLand fixes this across Greater Vancouver.

Do you repair Rheem furnaces you didn’t install?

Yes. HeatLand is brand-agnostic and services Rheem furnaces throughout Metro Vancouver and the Fraser Valley, whether or not we installed the unit. We carry common parts and give you an honest repair-or-replace assessment.

Is a Rheem furnace fault code an emergency?

No heat in cold weather is worth treating urgently. If you ever smell gas, leave the building and call your gas utility’s emergency line or 911 first. If a carbon-monoxide alarm sounds, get everyone out and call 911. A rollout or repeated limit trip can signal a heat-exchanger or venting problem — don’t keep resetting it. For priority furnace repair across Greater Vancouver, call (604) 330-3812.

How much does Rheem furnace repair cost in Vancouver?

It depends on the fault. Many Rheem codes point to sensors, ignition or pump parts — usually far cheaper than replacement. We give upfront pricing and a free estimate before any work.

More Furnace error-code guides

HeatLand repairs every major furnace brand across Greater Vancouver. More brand guides: