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

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

The codes below apply across common York models (Affinity, LX, Latitude). Meanings follow York’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 York furnace error codes

York furnace diagnostic LED flash codes

York furnace error codes & what they mean

These are the York 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
Slow GREEN flash	Normal operation with no call for heat (standby). The control board has power and is functioning. Slow flash is 2 seconds on / 2 seconds off DIY-checkable	Normal standby state, no fault present	No action needed; this indicates the furnace is powered and idle
Slow AMBER flash	Normal operation WITH a call for heat. The thermostat is calling for heat and the furnace is responding normally. Slow flash is 2 seconds on / 2 seconds off DIY-checkable	Normal heating cycle in progress, no fault present	No action needed; this indicates normal heating operation
LED steady OFF (no light)	No power to the control board, or a blown control-board fuse. If power is present and the fuse is intact, the board has failed and needs replacement DIY-checkable	Tripped breaker or furnace power switch off; Furnace blower-compartment door switch open (door not fully closed); Blown low-voltage fuse on the control board	Confirm the furnace switch (looks like a light switch near the furnace) is ON; Check the breaker for the furnace and reset it if tripped; Make sure the blower-compartment door is fully closed and seated
Steady ON (any color)	Internal control failure. Cycle power to the furnace; if the steady-on condition returns, the control board has failed and must be replaced pro repair	Control board internal fault or stuck relay; Line voltage / 24V supply problem detected by the board	Power-cycle the furnace once at the switch or breaker; Confirm the thermostat is set to Heat and the temperature is set above room temperature
Continuous / rapid GREEN flash	Twinning error: incorrect 24V phasing, or no power to a twinned (paired) furnace. Applies to twinned installations where two furnaces share a thermostat pro repair	Reversed 24V phasing between twinned furnaces; Incorrect twinning wiring; No power to the companion (twinned) unit	If your home has a single furnace this code should not appear; power-cycle once and contact a technician
Continuous / rapid AMBER flash	Flame sense current is below 1.5 microamps (weak flame signal). The furnace continues to run but the flame sensor signal is marginal pro repair	Dirty or oxidized flame sensor rod; Weak ground / poor electrical bonding; Marginal burner flame	Confirm the thermostat is set to Heat; Note: cleaning the flame sensor requires opening the burner area and is a licensed-technician task
1 RED flash	Flame sensed (or detected) when there should be none, i.e. flame present without a call for heat / with the gas valve de-energized. Typically a leaking or slow-closing gas valve pro repair	Leaking or slow-closing gas valve; Shorted flame sensor; Faulty control board	Power-cycle the furnace once at the switch or breaker; Confirm the thermostat is set to Heat
2 RED flashes	Pressure switch contacts are stuck/closed when they should be open (before the inducer starts) pro repair	Faulty pressure switch stuck closed; Miswiring at the pressure switch; Stuck relay on the control board	Power-cycle the furnace once at the switch or breaker; Make sure outdoor intake/exhaust vent terminals are clear of snow, ice, leaves, or nests
3 RED flashes	Pressure switch contacts are open when they should be closed (after the inducer is energized). The draft/venting cannot be confirmed pro repair	Faulty or weak inducer (draft) motor; Blocked vent or intake pipe; Disconnected, pinched, or broken pressure-switch hose/tubing	Make sure outdoor intake and exhaust vent terminals are clear of snow, ice, leaves, or debris; Power-cycle the furnace once at the switch or breaker
4 RED flashes	Main / primary limit switch opened (high-temperature limit), indicating an overheating condition usually caused by restricted airflow pro repair	Dirty or clogged air filter; Improperly sized or restricted duct system / closed registers; Incorrect blower speed setting	Inspect the air filter and clean or replace it if dirty; Make sure supply and return registers/vents are open and unobstructed; Power-cycle the furnace once after the filter is addressed
5 RED flashes	Flame rollout switch opened. This is a safety device that trips when flame or heat escapes the burner area; it indicates a potentially unsafe condition pro repair	Improper combustion air supply; Inducer (draft) motor malfunction; Cracked or failed primary heat exchanger	Make sure outdoor vent terminals are clear; Do not reset repeatedly; a tripped rollout switch can indicate an unsafe condition and should be inspected by a licensed technician
6 RED flashes	Pressure switch opened four times during a single call for heat. The control places the furnace in a soft lockout that automatically resets after one hour pro repair	Weak or failing inducer motor; Intermittent vent / intake restriction; Broken or loose pressure-switch hose	Make sure outdoor intake/exhaust terminals are clear of snow, ice, or debris; Power-cycle the furnace once; it may also auto-reset after one hour
7 RED flashes	Ignition lockout: flame was not established after three ignition attempts. The furnace locks out (typically auto-resets after one hour) pro repair	Gas supply off or low gas pressure; Faulty gas valve; Faulty or cracked hot-surface ignitor	Confirm the gas is turned on and other gas appliances (stove, water heater) work; Confirm the thermostat is set to Heat above room temperature; Power-cycle the furnace once; it may also auto-reset after one hour
8 RED flashes	Flame was established but then lost (dropout) five times during a single heating cycle. The control locks out (typically auto-resets after one hour) pro repair	Low or fluctuating gas pressure; Dirty or faulty flame sensor; Faulty gas valve	Confirm the gas is on and other gas appliances work; Power-cycle the furnace once; it may also auto-reset after one hour
9 RED flashes	Reversed line-voltage polarity, a grounding problem, or reversed low-voltage transformer wires. The control cannot verify correct AC polarity/ground pro repair	Reversed hot/neutral (line and neutral swapped) at the furnace or branch circuit; Poor or missing equipment ground; Flame probe shorted to chassis	Power-cycle the furnace once; Note: verifying polarity and grounding requires electrical testing and is a licensed-technician task
10 RED flashes	Gas valve energized (or gas flowing) without a call for heat. The control detects the gas valve circuit powered when it should not be pro repair	Faulty gas valve; Gas valve wiring fault / short; Faulty control board	Power-cycle the furnace once at the switch or breaker
11 RED flashes	Main / primary limit switch remained open for more than five minutes. This is a hard lockout that usually requires a manual power reset pro repair	Failed blower motor or blower wheel; Severe airflow restriction; Faulty limit switch	Inspect and clean/replace the air filter; Make sure registers/vents are open and unobstructed; Power-cycle the furnace once at the switch or breaker
4 AMBER flashes	Improper thermostat / low-voltage wiring: a cooling (Y) signal is present without a fan (G) signal. Normal operation continues but the wiring should be checked pro repair	Thermostat or low-voltage wiring fault (Y present without G); Loose or incorrect thermostat wire connection	Confirm the thermostat is set correctly (Heat/Cool/Auto and fan setting); Power-cycle the furnace once
1 GREEN flash	Normal operation with no current call for heat (on boards that use multi-flash green status codes). Indicates the board is healthy and idle DIY-checkable	Normal standby, no fault	No action needed

York furnace codes we get called for most

7 RED flashes — Ignition lockout: flame was not established after three ignition attempts. The furnace locks out (typically auto-resets after one hour)

Typical causes include gas supply off or low gas pressure; faulty gas valve; faulty or cracked hot-surface ignitor. A few things are safe to check yourself (Confirm the gas is turned on and other gas appliances (stove, water heater) work; Confirm the thermostat is set to Heat above room temperature), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 7 RED flashes on York furnaces throughout Greater Vancouver.

2 RED flashes — Pressure switch contacts are stuck/closed when they should be open (before the inducer starts)

Typical causes include faulty pressure switch stuck closed; miswiring at the pressure switch; stuck relay on the control board. A few things are safe to check yourself (Power-cycle the furnace once at the switch or breaker; Make sure outdoor intake/exhaust vent terminals are clear of snow, ice, leaves, or nests), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 2 RED flashes on York furnaces throughout Greater Vancouver.

4 RED flashes — Main / primary limit switch opened (high-temperature limit), indicating an overheating condition usually caused by restricted airflow

Typical causes include dirty or clogged air filter; improperly sized or restricted duct system / closed registers; incorrect blower speed setting. A few things are safe to check yourself (Inspect the air filter and clean or replace it if dirty; Make sure supply and return registers/vents are open and unobstructed), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 4 RED flashes on York furnaces throughout Greater Vancouver.

4 AMBER flashes — Improper thermostat / low-voltage wiring: a cooling (Y) signal is present without a fan (G) signal. Normal operation continues but the wiring should be checked

Typical causes include thermostat or low-voltage wiring fault (y present without g); loose or incorrect thermostat wire connection. A few things are safe to check yourself (Confirm the thermostat is set correctly (Heat/Cool/Auto and fan setting); Power-cycle the furnace once), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 4 AMBER flashes on York furnaces throughout Greater Vancouver.

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

Most York 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.

York furnace repair across Greater Vancouver

HeatLand has kept Metro Vancouver homes comfortable since 1999. Our licensed, insured technicians diagnose and repair York 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.

York furnace service areas

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

York furnace error code FAQs

Can I reset my York 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 York Continuous / rapid AMBER flash code mean?

On York furnaces, Continuous / rapid AMBER flash commonly indicates flame sense current is below 1.5 microamps (weak flame signal). the furnace continues to run but the flame sensor signal is marginal. 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 York furnaces you didn’t install?

Yes. HeatLand is brand-agnostic and services York 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 York 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 York furnace repair cost in Vancouver?

It depends on the fault. Many York 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: