Furnace Ignitor Keeps Failing | Hot Surface Ignitor, Flame Sensor, Control Board Portland
Furnace ignitor keeps failing? Complete Portland guide to hot surface ignitor issues, flame sensor problems, control board failures, electrical factors. Fix ignition failures and safety lockouts.
Read Time
15 min
Service Area
Portland Metro
License
CCB #187834
Owner & Lead HVAC Technician
A furnace ignitor that keeps failing is one of the most common and frustrating heating system problems Portland homeowners face. The ignitor is responsible for creating the spark or heat needed to ignite natural gas and start the combustion process. When it fails, your furnace can't produce heat, leaving you without warmth during our long, cold winters.
Modern furnaces use hot surface ignitors (silicon carbide rods that glow red-hot) rather than the older pilot light systems. These electronic ignition systems are more efficient but also more complex, with multiple components that can fail. Understanding ignition system failures and their causes can help you identify problems early and avoid costly emergency repairs.
This comprehensive guide covers the most common causes of ignitor failure, diagnostic procedures, repair options, and Portland-specific factors that can contribute to ignition problems.
How Furnace Ignition Works
When your thermostat calls for heat, the furnace control board sends power to the ignitor. The hot surface ignitor glows red-hot (about 2,500°F) for 30-60 seconds, then the gas valve opens to allow natural gas to flow. The ignitor's heat ignites the gas, creating a stable flame that the flame sensor detects to keep the gas flowing.
⚠️ Critical Safety Warning
Ignition system failures can lead to dangerous gas accumulation or carbon monoxide production. Never ignore repeated ignition failures - they indicate serious safety issues that require immediate professional attention.
Ignition Failure Symptoms & Urgency Levels
Furnace Won't Start
Failed ignitor, no power, control board issue
Check power, try manual reset, call service
Portland Cost: $150-400
Clicking Sound Without Ignition
Ignitor not glowing, gas valve not opening
Shut off gas, call professional immediately
Portland Cost: $200-500
Furnace Goes Into Lockout
Multiple ignition failures, safety system activation
Wait for lockout period, check error codes
Portland Cost: $100-300
Ignitor Glows But No Flame
Gas valve stuck, low gas pressure, dirty burner
Shut off gas valve, call emergency service
Portland Cost: $300-600 + emergency
Weak Flame or Delayed Ignition
Dirty ignitor, weak gas pressure, control board issue
Clean components, check gas pressure
Portland Cost: $150-350
Frequent Error Codes
Control board detecting ignition problems
Note error code, schedule service
Portland Cost: $100-250
Most Common Causes of Ignitor Failure
Failed Hot Surface Ignitor
Description:
Silicon carbide ignitor wears out after 3-5 years of heating cycles
Symptoms:
No glow when starting, clicking without ignition, lockouts
Diagnosis:
Visual inspection shows cracked or cloudy ignitor
Solution:
Replace ignitor ($150-300)
Frequency:
Every 3-5 years
Danger Level:
Medium - prevents furnace operation
Portland Note:
Cold weather increases failure rate
Dirty Flame Sensor
Description:
Carbon buildup prevents flame detection, causing false shutdowns
Symptoms:
Furnace starts then shuts down immediately
Diagnosis:
Black carbon coating on sensor tip
Solution:
Clean sensor with steel wool ($0-50)
Frequency:
Annual cleaning needed
Danger Level:
Low - safety shutdown prevents issues
Portland Note:
Yellow flames increase carbon buildup
Control Board Failure
Description:
Electronic control board fails due to age, power surges, or moisture
Symptoms:
Multiple error codes, erratic operation, no ignitor power
Diagnosis:
Test voltage outputs, check for error codes
Solution:
Replace control board ($200-500)
Frequency:
Every 10-15 years
Danger Level:
High - affects multiple furnace functions
Portland Note:
Humidity and power quality issues accelerate failure
Gas Valve Problems
Description:
Gas valve fails to open or close properly, preventing ignition
Symptoms:
No gas flow, weak flame, furnace won't start
Diagnosis:
Check voltage to valve, test continuity
Solution:
Replace gas valve ($200-400)
Frequency:
Every 10-15 years
Danger Level:
High - gas safety issue
Portland Note:
Cold weather affects valve operation
Low Gas Pressure
Description:
Insufficient gas pressure prevents proper ignition and flame
Symptoms:
Weak flame, delayed ignition, frequent failures
Diagnosis:
Measure manifold pressure with gauge
Solution:
Adjust regulator or call gas company ($100-300)
Frequency:
Check annually
Danger Level:
Medium - affects combustion efficiency
Portland Note:
NW Natural pressure can vary seasonally
Electrical Problems
Description:
Poor wiring connections, voltage issues, or ground faults
Symptoms:
Intermittent operation, ignitor not glowing, control board errors
Diagnosis:
Check wiring connections, test voltage
Solution:
Repair wiring, improve electrical ($150-400)
Frequency:
Every 5-7 years
Danger Level:
Medium - can cause component damage
Portland Note:
Older Portland homes often have wiring issues
Types of Furnace Ignition Systems
Hot Surface Ignitor
Description:
Silicon carbide rod that glows red-hot to ignite gas
Advantages:
Reliable, efficient, long lifespan
Disadvantages:
Can fail suddenly, expensive to replace
Lifespan:
3-5 years
Cost:
$150-300
Portland Suitability:
Standard in most modern furnaces, good reliability
Spark Ignitor
Description:
Creates spark to ignite gas, similar to gas stove
Advantages:
Cheap to replace, easy diagnosis
Disadvantages:
Noisy, can be less reliable in cold weather
Lifespan:
5-7 years
Cost:
$50-150
Portland Suitability:
Less common in Portland, spark can be affected by humidity
Pilot Light System
Description:
Continuous small flame that ignites main burners
Advantages:
Simple, reliable in cold weather
Disadvantages:
Wastes small amount of gas continuously
Lifespan:
Control: 10-15 years, Thermocouple: 3-5 years
Cost:
$100-250
Portland Suitability:
Common in older Portland homes, reliable in damp conditions
Intermittent Pilot
Description:
Electronic ignition with spark that lights pilot when needed
Advantages:
Energy efficient, reliable
Disadvantages:
More complex electronics
Lifespan:
5-8 years
Cost:
$200-400
Portland Suitability:
Good for modern Portland homes, handles humidity well
Hot Surface Ignitors Most Common in Portland
Most modern furnaces installed in Portland use hot surface ignitors due to their reliability and efficiency. While they occasionally fail, they're generally more dependable than older spark ignition systems. Regular maintenance and prompt replacement when they fail prevent most ignition problems.
Annual furnace tune-ups catch ignitor problems before they cause complete system failure.
Step-by-Step Ignition System Diagnosis
Safety First - Gas and Power Off
Action:
Locate and turn off gas shutoff valve, turn off furnace power at breaker. Have phone ready for emergency.
Tools:
None - safety preparation
Time: 5 minutes
Visual Inspection
Action:
Remove furnace access panel, inspect ignitor for cracks/cloudiness, check wiring connections.
Tools:
Flashlight, screwdriver
Time: 10-15 minutes
Ignitor Functionality Test
Action:
Restore power (gas still off), initiate furnace start cycle, observe if ignitor glows.
Tools:
None - observation
Time: 5 minutes
Error Code Check
Action:
Check furnace control board or thermostat for error codes, note specific numbers.
Tools:
None - reading display
Time: 2-3 minutes
Gas Pressure Test
Action:
Have professional measure manifold gas pressure with specialized gauge.
Tools:
Manifold pressure gauge
Time: 15-30 minutes
Control Board Testing
Action:
Professional testing of voltage outputs and component communication.
Tools:
Multimeter, diagnostic tools
Time: 30-60 minutes
Critical Safety Considerations
⚠️ Gas Leak Hazard
Description:
Failed ignition can allow gas to accumulate without burning
Warning Signs:
Gas odor, hissing sounds, dead plants near furnace
Immediate Action:
Evacuate, shut off gas, call emergency services
Prevention:
Regular maintenance and prompt repair of ignition issues
⚠️ Carbon Monoxide Poisoning
Description:
Improper combustion or delayed ignition can produce CO
Warning Signs:
Headache, dizziness, nausea, confusion
Immediate Action:
Get fresh air, call emergency services, install CO detectors
Prevention:
Annual furnace inspection and CO detector installation
⚠️ Electrical Shock
Description:
Ignition system operates on 120V with control voltages
Warning Signs:
Exposed wires, damaged insulation, tripped breakers
Immediate Action:
Turn off power, seek professional help
Prevention:
Professional installation and repairs only
⚠️ Fire Hazard
Description:
Hot ignitor or gas leaks near ignition source
Warning Signs:
Burning smells, visible flames where shouldn't be
Immediate Action:
Shut off gas and electricity, evacuate, call fire department
Prevention:
Regular cleaning and maintenance of ignition components
Carbon Monoxide Detection Essential
Ignition system failures are a leading cause of carbon monoxide poisoning in homes. Every Portland home should have interconnected CO detectors on every floor and outside sleeping areas. Test them monthly and replace batteries annually. If a detector alarms, evacuate immediately and call emergency services.
CO detectors cost $30-100 and can save lives - install them today if you don't have them.
Portland-Specific Ignition Challenges
Cold Weather Performance
Local Impact:
Extreme cold affects ignitor resistance and gas valve operation
Solution:
Winter furnace tune-up, ignitor replacement before cold snap
Annual Cost:
$150-300 annual winter service
Health & Cost Savings:
Prevents emergency calls during cold weather
High Humidity Effects
Local Impact:
Pacific Northwest humidity causes corrosion and moisture issues
Solution:
Annual cleaning, corrosion-resistant components
Annual Cost:
$100-200 annual maintenance
Health & Cost Savings:
Extends component life 2-3 years
Power Quality Issues
Local Impact:
Variable electrical quality in some Portland neighborhoods
Solution:
Install surge protector, monitor power quality
Annual Cost:
$50-150 protection
Health & Cost Savings:
Prevents $300-500 component replacement
Gas Pressure Variations
Local Impact:
NW Natural gas pressure can vary with demand and weather
Solution:
Annual pressure testing, regulator maintenance
Annual Cost:
$100-200 annual check
Health & Cost Savings:
Prevents chronic ignition problems
Older Home Electrical
Local Impact:
Pre-1980s Portland homes often have inadequate electrical systems
Solution:
Electrical upgrade or dedicated furnace circuit
Annual Cost:
$300-600 electrical work
Health & Cost Savings:
Eliminates chronic ignition and electrical problems
Pollen and Dust Loading
Local Impact:
High pollen seasons load air filters, restricting furnace airflow
Solution:
Weekly filter checks during pollen season
Annual Cost:
$50-100 seasonal maintenance
Health & Cost Savings:
Prevents $200-400 ignition system repairs
Prevention Through Portland-Specific Maintenance
Portland homeowners can prevent 85% of ignition system failures through proactive maintenance. Annual tune-ups, filter changes during pollen season, and electrical system checks address the specific challenges of our climate. These preventive measures cost $250-400 annually but prevent $800-1,500 emergency repairs and ensure safe, reliable heating.
Annual furnace maintenance prevents dangerous ignition failures and saves $600+ per year in Portland.
When to Call Professional Service
🚨 Emergency Service Required
- •Gas odor in home
- •Carbon monoxide detector alarms
- •Furnace won't start and temperatures below 50°F
- •Hissing or unusual gas sounds
- •Visible gas flames where they shouldn't be
- •You're uncomfortable working with gas systems
🔧 Schedule Service Soon
- •Furnace ignites but flame looks weak or yellow
- •Delayed ignition (longer than 30 seconds)
- •Furnace is over 8 years old
- •Annual maintenance is 12+ months overdue
- •Error codes appear on thermostat
- •Planning to replace furnace soon
Why Professional Ignition Service Matters
Furnace ignition systems involve complex interactions between gas, electricity, and combustion. Licensed technicians can properly diagnose problems, test gas pressures, ensure proper flame characteristics, and verify all safety systems function correctly. In Portland, where gas pressure can vary and humidity affects electrical components, professional expertise ensures your heating system operates safely throughout our variable climate.
A $200 ignition system inspection can prevent $1,000+ in damage and ensure your family's safety and comfort.