Furnace Troubleshooting
Furnace Ignitor Replacement Ontario 2026: Hot Surface Ignitor Symptoms, Diagnosis, and Fair Pricing
A furnace that fires three times and locks out cold on a January morning is almost always an ignitor, not a new furnace. This guide covers how the hot surface ignitor works, how it fails, what a fair repair costs in Ontario in 2026, and the red flags that separate a routine service call from an upsell attempt.
Key Takeaways
- The hot surface ignitor (HSI) is a silicon carbide or silicon nitride element that glows to ignite the burner on modern mid and high-efficiency furnaces.
- Typical lifespan is 3 to 7 heating seasons; newer silicon nitride elements outlast older silicon carbide.
- Classic failure signature: three ignition attempts, then a lockout and cold air from the registers.
- A healthy HSI reads 40 to 75 ohms cold on a multimeter; open circuit or above 200 ohms confirms failure.
- Fair Ontario 2026 pricing: $200 to $400 all-in for diagnosis, part, and labour.
- Universal ignitors (Supco, Robertshaw, Honeywell) fit roughly 95 percent of furnaces and cost far less than OEM.
- An ignitor that fails in under two years is usually a symptom of short-cycling or a wrong ignition delay setting, not a bad part.
What the Hot Surface Ignitor Does
On a modern gas furnace installed in Ontario since the mid-1990s, the standing pilot light is gone. In its place sits a hot surface ignitor, typically a small silicon carbide or silicon nitride element about the size of a pencil stub, mounted at the edge of the burner assembly.[3]During a heat call the furnace control board sends 120V AC directly to the element, which heats to roughly 1,200 degrees Celsius within 15 to 30 seconds. Once the board confirms the ignitor has reached temperature it opens the gas valve; the gas ignites off the glowing element, and the flame sensor takes over to confirm combustion.
Silicon nitride elements, which replaced older silicon carbide designs on most furnaces manufactured after roughly 2010, are more durable and tolerate more ignition cycles before cracking. Either type is still a consumable wear part; no HSI lasts the life of the furnace.[5]
How an Ignitor Fails
A typical hot surface ignitor lasts 3 to 7 heating seasons in the Ontario climate. Failure happens one of three ways: the ceramic element cracks from thermal stress during repeated heat-cool cycles, corrosion or contamination creates hot spots that eventually sever the element, or the resistance of the element drifts out of range so it no longer reaches ignition temperature fast enough for the control board's trial-for- ignition window.
Older silicon carbide ignitors fail noticeably more often than newer silicon nitride elements. A furnace still running its original carbide ignitor in year eight is borrowed time; a silicon nitride element in year five is usually fine.
Symptoms of a Failed Ignitor
The classic signature is the three-try lockout. The furnace control board attempts ignition, fails to confirm flame, purges, tries again, fails again, purges, tries a third time, and then locks out. The furnace runs the inducer and blower briefly and then shuts down entirely, blowing cold air through the registers until the thermostat is reset or the power is cycled.
- No orange glow visible through the burner sight glass during the ignition sequence
- Control board flashing an ignition-failure diagnostic code (legend on the inside of the burner cover)
- Furnace cycling on and off with cold-air bursts before fully locking out
- Clicking from the gas valve followed by no ignition
- Thermostat calling for heat, inducer running, blower running, but no flame
A few of these symptoms overlap with flame sensor or pressure switch faults. The diagnostic sequence below is how a technician narrows it down.[3]
How a Technician Diagnoses the Ignitor
Four checks, in order. Any competent furnace tech runs them in under fifteen minutes.
| Step | Check | Pass | Fail |
|---|---|---|---|
| 1 | Visual check through the sight glass during a heat call | Bright orange glow within 30 seconds | No glow, or dim red glow only |
| 2 | Pull the ignitor and inspect for cracks or corrosion | Clean ceramic, intact element | Visible cracks, chipping, or heavy corrosion |
| 3 | Measure resistance across the leads with a multimeter | 40 to 75 ohms cold | Open circuit, or above 200 ohms |
| 4 | Verify 120V AC at the ignitor terminals during ignition | 120V present during the ignition window | No voltage (control board or wiring fault) |
If step 3 fails, the ignitor is the culprit. If step 3 passes but step 4 fails, the control board or the wiring harness feeding the ignitor is the problem, and replacing the ignitor will not fix anything.[3]
The DIY Caution
The hot surface ignitor is a low-cost part and the physical swap takes about ten minutes. Two real cautions apply.
First, the ignitor sits in a 120V AC circuit and the furnace control board can hold stored charge after the power is cut. Power must be isolated at both the furnace service switch and the breaker before any component work. The Electrical Safety Authority of Ontario's homeowner guidance treats 120V furnace component work as low-voltage electrical that a confident homeowner may perform, but any work inside the gas train is a different story.[4]
Second, the silicon carbide or silicon nitride element must never be touched with bare fingers. Skin oils transfer to the ceramic and create hot spots that concentrate thermal stress and cause premature failure within weeks. Handle the new ignitor only by its ceramic base or through a clean dry cloth.
Ignitor work itself is not gas work and does not require TSSA G2 or G3 gas technician licensing.[1]However, combustion verification after the repair is best done by a licensed gas tech, because incomplete combustion produces carbon monoxide. The safe default for most households is to pay the service call, let the tech swap the part, and let them verify burner operation before closing the cabinet.[2]
Fair Ontario 2026 Pricing
Ignitor replacement is one of the most common residential furnace service calls, and pricing should be straightforward. The job is 15 to 30 minutes of labour and a part that wholesales for well under $100.
| Line Item | Ontario 2026 Range | Notes |
|---|---|---|
| Diagnostic service call | $180 to $280 | Typically credited toward repair if job proceeds |
| Universal HSI (Supco, Robertshaw, Honeywell) | $30 to $60 part, $40 to $80 installed markup | Fits roughly 95 percent of residential furnaces |
| OEM HSI (Carrier, Lennox, Trane, York) | $60 to $150 part, $90 to $200 installed markup | Required only for a handful of proprietary models |
| Labour for the swap | $50 to $150 | 15 to 30 minutes on a straightforward unit |
| All-in typical total | $200 to $400 | Higher on weekend, after-hours, or rural calls |
A quote above $500 on an ignitor-only repair deserves scrutiny. A quote that bundles the ignitor with a control board, gas valve, or full burner assembly without failing any of the diagnostic steps above is an upsell. Universal ignitors work for the vast majority of installations; do not let a contractor gold-plate the bill with a $200 OEM part when a $40 universal does the job.
When the Ignitor Fails Young: Look Upstream
An HSI that fails in under two years is almost never a bad part. It is a symptom. Two root causes dominate.
The first is short-cycling. A furnace that is oversized, has a dirty filter, has a plugged condensate trap, or has a failing flame sensor will cycle on and off every few minutes instead of running in longer steady burns. Every cycle puts a full thermal shock on the ignitor. An HSI that normally lasts five years will fail inside two if the furnace is cycling three times as often as it should.
The second is a wrong ignition delay setting on the control board. Most manufacturers specify a hold time between the ignitor reaching temperature and the gas valve opening; if the delay is set too short, the ignitor is still heating when the gas hits, which cracks the element faster. The correct setting is in the manufacturer's installation manual for the specific furnace model.[3]
A technician replacing a second ignitor within two years should be asked to check both. Replacing the part again without fixing the root cause just resets the clock on the next failure.
Red Flags on a Quote
A few patterns turn up repeatedly on Ontario service calls. Any of them should trigger a second opinion before signing.
- “You need a new ignition control module” without the technician having measured resistance on the HSI or confirmed 120V at the terminals. The module is a $400 to $1,100 part; the ignitor is a $40 part. The ignitor gets tested first.
- “The whole furnace needs replacing” on a unit under 12 years old with no other diagnosed failure. An ignitor repair on a 10-year-old furnace is $300, not $9,500.
- The technician sanding or cleaning the ignitor with emery paper or a wire brush and putting it back in. A dirty ignitor is already close to failure; cleaning a silicon carbide or silicon nitride element is not a repair and typically damages the ceramic further.
- A quote that does not itemize parts, labour, and diagnostic call. Section 21 of Ontario's Consumer Protection Act, 2002 and its regulations require written estimates for repair work over a specified threshold; an itemized quote is the baseline, not a courtesy.[7]
- “OEM only, no substitutes” on a mainstream brand (Carrier, Lennox, Trane, York, Goodman, Rheem, Amana, Bryant). Universal ignitors from Supco, Robertshaw, or Honeywell carry the same approvals and work on those platforms.
Where the Ignitor Call Sits in the Bigger Picture
An ignitor replacement on a furnace inside its useful life is the canonical repair-every-time call. The conversation changes on a 15-plus-year furnace where the ignitor is the third repair in two seasons; cumulative repair spend can push the decision into replacement territory.[5]For that framework see our repair-versus-replace guide below. For a broader read on what a furnace service call should actually cover and cost, see the service- call guide.[6]
Frequently Asked Questions
What does the hot surface ignitor do on a modern gas furnace?
The hot surface ignitor (HSI) is the silicon carbide or silicon nitride element that replaces the old standing pilot light on modern mid and high-efficiency gas furnaces. During a heat call the furnace control board sends 120V AC directly to the HSI, which heats to roughly 1,200 degrees Celsius within 15 to 30 seconds. The gas valve then opens and the burner ignites off the glowing element. After ignition the board cuts power to the HSI and hands off to the flame sensor, which confirms the flame is present.
What are the symptoms of a failed hot surface ignitor?
The most common symptom is a furnace that attempts ignition three times then locks out, blowing cold air until the thermostat is reset or the power is cycled. Through the sight glass on the burner compartment no orange glow is visible during the ignition sequence. The control board typically flashes a diagnostic code for ignition failure; the legend is printed on the inside of the burner cover. Some homeowners notice the furnace cycling on and off intermittently with cold-air bursts before it fully locks out.
How does a technician diagnose a bad ignitor?
A technician runs four checks. First, a visual check through the sight glass during a heat call to confirm whether the element glows. Second, the ignitor is pulled and inspected for visible cracks, chips, or heavy corrosion. Third, the resistance is measured across the element leads with a multimeter; a healthy HSI reads between 40 and 75 ohms cold, while an open circuit or a reading above 200 ohms confirms failure. Fourth, 120V AC is verified at the ignitor terminals during the ignition sequence to rule out a control board or wiring fault.
What should a fair furnace ignitor replacement cost in Ontario?
Ontario 2026 pricing for a diagnostic call runs $180 to $280, the part itself runs $30 to $90 with a typical $40 to $90 markup, and labour for the actual swap is 15 to 30 minutes at $50 to $150. The all-in total should land between $200 and $400 on a straightforward call. A universal ignitor from Supco, Robertshaw, or Honeywell fits roughly 95 percent of residential furnaces and costs less than an OEM part. A quote above $500 without a legitimate secondary issue deserves a second opinion.
Can I replace the hot surface ignitor myself?
The physical swap is about ten minutes: turn off power at the furnace switch and breaker, remove the burner cover, unclip the ignitor wiring harness, unscrew the bracket, and install the new element. Two real cautions apply. The ignitor sits in a 120V circuit and furnace control boards can hold stored charge, so power must be fully isolated before touching anything. More importantly, never touch the silicon carbide or silicon nitride element with bare fingers; skin oils transfer to the element and create hot spots that cause premature failure within weeks. Handle only by the ceramic base or through a clean cloth.
Do I need a TSSA-licensed gas technician to replace an ignitor?
The ignitor itself is a low-voltage replaceable component and is not gas work under TSSA G2 or G3 licensing requirements. A qualified electrician or a confident homeowner can physically swap the part. However, combustion verification after any work that affects the ignition sequence is best performed by a licensed gas technician, because incomplete combustion produces carbon monoxide. The safe path for most households is to pay a tech the service-call fee, let them swap the part, and have them verify burner operation before closing up.
Related Guides
- Furnace Flame Sensor Issues Ontario 2026
- Furnace Pressure Switch Issues Ontario 2026
- Furnace Short Cycling Troubleshooting Ontario 2026
- Technical Standards and Safety Authority (TSSA) Fuels Safety: Gas Appliance Installation and Service Requirements
- CSA Group CSA B149.1: Natural Gas and Propane Installation Code
- Heating, Refrigeration and Air Conditioning Institute of Canada (HRAI) Residential Furnace Service and Component Reference Guidance
- Electrical Safety Authority of Ontario (ESA) Ontario Electrical Safety Code and Homeowner Electrical Work
- Natural Resources Canada Energy Efficiency for Homes: Heating Equipment
- ENERGY STAR Canada Furnaces Product Specifications
- Government of Ontario Consumer Protection Act, 2002, S.O. 2002, c. 30, Sched. A