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

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

The codes below apply across common Tempstar models (Ion, standard ICP). Meanings follow Tempstar’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 Tempstar furnace error codes

Amber LED status light on the furnace control board. A steady 'heartbeat' (bright-dim-bright-dim) means the control has power and no fault. Faults are shown as a status code: the first number is the count of SHORT flashes; on two-stage/variable-speed (Ion / modulating) boards a second number after a '+' is the count of LONG flashes (e.g. 4 + 2). LED ON SOLID means a soft lockout / internal control fault. On many single-stage boards the code is just a single flash count (2-10).

Tempstar furnace error codes & what they mean

These are the Tempstar 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
LED off / continuous off	No power to the control. Check 115 VAC at L1 and L2, 24 VAC at the secondary transformer terminals, and the 24V control fuse pro repair	Tripped breaker or furnace disconnect switch off; Blown 24V control board fuse; Failed low-voltage transformer	Confirm the furnace power switch (looks like a light switch on or near the furnace) is ON; Check the breaker for the furnace and reset it once if tripped; Confirm the furnace front panel/blower door is fully closed (a safety switch cuts power if it is open)
Heartbeat (bright-dim-bright-dim)	Normal operation. The control has 24 VAC power and no fault is stored. This is the expected healthy condition, not an error DIY-checkable		No action needed; this indicates the control is powered and healthy
LED on solid	Soft lockout / furnace control error. The control is locked out and will auto-reset after about 1 hour. Possible causes include a flame-sense circuit failure, gas valve relay stuck open, or an internal software check error. If it returns after a power reset, the control board is replaced pro repair	Internal control board fault; Flame-sense circuit failure; Gas valve relay stuck open	Turn the furnace power switch off, wait about 30 seconds, then back on once to attempt a single reset; Confirm the thermostat is set to Heat with the setpoint above room temperature
2	Pressure switch did not open. The pressure switch was found closed when it should have been open (typically before the inducer starts) pro repair	Obstructed pressure tubing; Pressure switch stuck closed; Defective pressure switch	Confirm the outdoor intake and exhaust vent terminals are clear of snow, ice, leaves, nests, or debris; Cycle furnace power once (off ~30 seconds, then on)
3	Low pressure switch did not close or reopened. The pressure switch failed to close on a call for heat, or opened during operation. This usually points to a venting or inducer/draft problem pro repair	Improper or restricted vent sizing; Restricted or blocked intake/exhaust vent; Plugged condensate drain	Check that the intake and exhaust vent terminals outside are completely clear of snow, ice, or debris; Confirm no obvious water pooling or sagging in visible vent piping; Cycle furnace power once
4	Limit circuit fault. The high-limit or flame rollout switch is open, or the furnace tripped on limit and is restricted to maximum-heat-only mode after successive limit trips. Often caused by overheating from restricted airflow. The flame rollout switch requires a manual reset by a technician. If the limit stays open longer than about 3 minutes the code escalates to lockout code 7 pro repair	Dirty air filter; Restricted or undersized ductwork / closed registers; Loose or dragging blower wheel	Replace or clean the air filter if dirty; Make sure supply and return registers/vents inside the home are open and unblocked; Confirm nothing is obstructing return-air grilles
5	Abnormal flame-proving signal. Flame is being sensed while the gas valve is de-energized (flame present when it should not be). The inducer will run until the fault clears. This is a safety-significant condition pro repair	Leaky gas valve; Stuck-open gas valve; Control board flame-sense fault	Confirm the thermostat is set correctly; Do not attempt internal repairs; this involves the gas valve and requires a licensed technician
6	Ignition-proving failure. The furnace failed to light or lost the flame signal. The control will retry up to three more times before going to ignition lockout (code 6 + 1) pro repair	Low inlet gas pressure; Gas valve turned off, defective, or manual valve shut off; Defective hot surface igniter	Confirm the gas supply is on (check that other gas appliances such as a stove or water heater work); Confirm the furnace power switch is on and thermostat is set to Heat; Cycle furnace power once to allow a fresh ignition attempt
7	Limit circuit lockout. Lockout occurs if the limit or flame rollout switch stays open longer than about 3 minutes, or after 10 successive limit trips during maximum-heat. The control auto-resets after about 3 hours. Related to code 4 (limit circuit fault) pro repair	Persistent overheating from dirty filter or restricted airflow; Blocked ducts or registers; Failed blower motor	Replace or clean the air filter; Open and unblock all supply/return registers and return grilles; Cycle furnace power once after airflow is restored
8	Gas heating lockout. The control will NOT auto-reset. Typically caused by a stuck-closed gas valve relay on the control, or a miswire/short to the gas valve wire pro repair	Stuck-closed gas valve relay on the control board; Miswire or short to the gas valve wire; Control board fault	Cycle furnace power once; if the lockout persists a technician is required (this is a safety lockout involving the gas valve)
9	Medium pressure switch, high pressure switch, or PSR relay did not close or reopened. The medium/high pressure switch failed to close on a call for intermediate- or maximum-heat, or opened during a heating cycle. Related to code 3. Applies to two-stage / modulating (Ion) boards that use multiple pressure switches pro repair	Restricted or improper venting; Plugged condensate drain; Defective medium or high pressure switch	Confirm intake/exhaust vent terminals are clear of obstructions; Cycle furnace power once
10	Polarity. Line-voltage (115 VAC) polarity is reversed. If two furnaces are twinned, it can also indicate improper 24V transformer phasing. Correct polarity is required for the flame-sensing circuit to work pro repair	Reversed line (hot/neutral) wiring at the furnace or outlet; Improper low-voltage transformer phasing on twinned units	No safe homeowner check; correcting line-voltage polarity requires a licensed electrician or HVAC technician
1 + 2	Blower on after power up. Normal operation, not a fault. The blower runs for 90 seconds if the unit is powered up during a call for heat, or if the heat call opens during the blower on-delay period DIY-checkable		No action needed; this is normal post-power-up behavior
1 + 5	Blower motor lockout. The blower failed to reach 250 RPM or failed to communicate within 30 seconds after being turned on, in two successive heating cycles. The control auto-resets after about 3 hours. Related to code 4 + 1 pro repair	Failed ECM blower motor; Blower motor wiring/communication fault; Control board fault	Replace a dirty air filter and ensure return-air grilles are unobstructed; Cycle furnace power once
2 + 5	Model selection or setup error. If it flashes only 4 times on power-up, the control is missing its model plug and is using the model stored in memory. If it flashes continuously it can mean a missing model plug with no valid stored model, a setup switch left on, two different furnace models twinned, or an incorrect/old-software service replacement control pro repair	Missing model plug PL4 on a replacement control; Setup (DIP) switch left in the ON position; Two different furnace models twinned together	This is a service/setup error typically seen after board replacement; a licensed technician must verify the model plug and setup switches
3 + 5	Gas valve fault. The modulating gas valve failed to respond to a command from the control, or power to the gas valve electronics was interrupted. Check for intermittent wiring at the gas valve or the PL8 connection pro repair	Intermittent red, yellow, or orange wire at the modulating gas valve; Loose PL8 connector; Defective modulating gas valve	Confirm the thermostat is set to Heat; do not open or service the gas valve. A licensed technician is required.
4 + 1	Blower motor fault. The blower failed to reach 250 RPM or failed to communicate within the prescribed time limits (30 seconds after start, or 10 seconds during steady-state operation) pro repair	Failed ECM blower motor; Blower motor wiring or communication fault; Obstructed or seized blower wheel	Replace a dirty filter and ensure registers/return grilles are open; Cycle furnace power once
4 + 2	Inducer motor fault. The inducer did not start within 20 seconds of a call for heat, its RPM is outside the valid range, or the RPM signal was lost for 5 seconds during operation pro repair	Failed inducer motor; Improper or restricted vent sizing; Restricted vent	Confirm intake/exhaust vent terminals outside are clear of debris, snow, or ice; Cycle furnace power once
4 + 3	Low or medium pressure switch open while medium or high pressure switch is closed. An out-of-sequence pressure switch condition on multi-stage boards pro repair	Low inlet gas pressure (if a low gas pressure switch is used); Plugged condensate drain; Improper pressure switch wiring	Check that vent terminals are clear and there is no visible water pooling in vent piping; Cycle furnace power once
6 + 1	Ignition lockout. The furnace failed to ignite after its retry attempts. The control auto-resets after about 3 hours. Related to code 6 (ignition-proving failure) pro repair	Low or no inlet gas pressure; Gas supply off or manual valve shut off; Defective hot surface igniter	Confirm the gas supply is on by checking that another gas appliance (stove, water heater) works; Confirm the furnace switch and thermostat (set to Heat) are correct; Cycle furnace power once to allow a fresh ignition sequence; if lockout repeats, call a technician

Tempstar furnace codes we get called for most

6 — Ignition-proving failure. The furnace failed to light or lost the flame signal. The control will retry up to three more times before going to ignition lockout (code 6 + 1)

Typical causes include low inlet gas pressure; gas valve turned off, defective, or manual valve shut off; defective hot surface igniter. A few things are safe to check yourself (Confirm the gas supply is on (check that other gas appliances such as a stove or water heater work); Confirm the furnace power switch is on and thermostat is set to Heat), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 6 on Tempstar furnaces throughout Greater Vancouver.

2 — Pressure switch did not open. The pressure switch was found closed when it should have been open (typically before the inducer starts)

Typical causes include obstructed pressure tubing; pressure switch stuck closed; defective pressure switch. A few things are safe to check yourself (Confirm the outdoor intake and exhaust vent terminals are clear of snow, ice, leaves, nests, or debris; Cycle furnace power once (off ~30 seconds, then on)), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 2 on Tempstar furnaces throughout Greater Vancouver.

4 — Limit circuit fault. The high-limit or flame rollout switch is open, or the furnace tripped on limit and is restricted to maximum-heat-only mode after successive limit trips. Often caused by overheating from restricted airflow. The flame rollout switch requires a manual reset by a technician. If the limit stays open longer than about 3 minutes the code escalates to lockout code 7

Typical causes include dirty air filter; restricted or undersized ductwork / closed registers; loose or dragging blower wheel. A few things are safe to check yourself (Replace or clean the air filter if dirty; Make sure supply and return registers/vents inside the home are open and unblocked), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 4 on Tempstar furnaces throughout Greater Vancouver.

1 + 2 — Blower on after power up. Normal operation, not a fault. The blower runs for 90 seconds if the unit is powered up during a call for heat, or if the heat call opens during the blower on-delay period

Typical causes include a few related faults. A few things are safe to check yourself (No action needed; this is normal post-power-up behavior), but the repair is a licensed, TSBC-certified gas technician job. HeatLand diagnoses and fixes 1 + 2 on Tempstar furnaces throughout Greater Vancouver.

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

Most Tempstar 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.

Tempstar furnace repair across Greater Vancouver

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

Tempstar furnace service areas

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

Tempstar furnace error code FAQs

Can I reset my Tempstar 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 Tempstar 6 code mean?

On Tempstar furnaces, 6 commonly indicates ignition-proving failure. the furnace failed to light or lost the flame signal. the control will retry up to three more times before going to ignition lockout (code 6 + 1). 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 Tempstar furnaces you didn’t install?

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

It depends on the fault. Many Tempstar 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

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