Why Your Wall Heater/Furnace Pilot Light Won’t Stay Lit (And When to Call a Pro)

Quick Answer

A wall heater or furnace pilot light usually won’t stay lit because of a dirty pilot, a bad thermocouple or flame sensor, or a failing gas valve. Some issues are simple, but repeated outages or any gas-related concerns should be inspected by a licensed professional.

Why Your Pilot Light Won’t Stay Lit

Pilot-light failures are one of the most common heating issues we see in Steubenville, Wintersville, Weirton, Toronto, Mingo Junction, Brilliant, Follansbee, Wellsburg, New Cumberland, and Colliers. When the flame keeps going out, homeowners want to know whether it’s dangerous, whether it’s a simple fix, or whether the system is trying to warn them of something bigger.

Wall heaters and furnaces rely on safety systems that shut the gas off if anything appears unsafe. When the pilot won’t stay lit, it’s often the system protecting you.

How Wall Heaters and Furnaces Light Themselves

Wall Heaters (Gas Wall Units)

Most gas wall heaters use:

• A standing pilot light, or
• An electronic igniter

Older wall heaters rely on a thermocouple, which must detect heat from the pilot flame before allowing gas flow.

Furnaces (Forced-Air Heating)

Modern furnaces use:

• Hot-surface igniters
• Flame sensors
• Multiple safety switches
• Electronic control boards

Older furnaces may still use standing pilots similar to wall heaters.

If the pilot won’t stay lit, it means the safety system cannot confirm the flame — and automatically shuts off gas.

Most Common Causes (and What They Mean)

1. Dirty Pilot Orifice

Dust, rust flakes, or lint can partially block the tiny pilot opening. A weak, soft, or yellow flame cannot heat the sensor properly.

Solution: cleaning or replacing the pilot assembly.

2. Failing Thermocouple (Wall Heaters & Older Furnaces)

The thermocouple proves the flame is present. If it’s dirty, weak, bent, or failing, the system shuts down immediately.

Common signs:

• Pilot stays lit only while holding the button
• Flame goes out immediately after releasing

Solution: thermocouple cleaning or replacement.

3. Bad Flame Sensor (Modern Furnaces)

A dirty or failing flame sensor causes the furnace to light briefly, then shut off.

Signs:

• Furnace lights, then shuts off in seconds
• Constant short cycling

Solution: flame sensor cleaning or replacement.

4. Faulty Gas Valve

If the gas valve doesn’t regulate flow properly, the pilot will be unstable or weak.

Symptoms: lazy flame, inconsistent flame height, repeated shutdowns.

Solution: gas valve testing and replacement if needed.

5. Drafts or Airflow Problems

Wall heaters located in hallways, basements, or near exterior doors often experience drafts that blow the pilot light out.

Solution: sealing drafts or adjusting the heater’s location.

6. Cracked Heat Exchanger (Furnaces)

A cracked heat exchanger can cause burner instability and trigger safety shutdowns. This is a serious safety issue and should be addressed immediately.

Solution: heat-exchanger replacement or full furnace replacement.

7. Venting or Carbon-Monoxide Issues

If flues or vents are blocked or back-drafting, built-in safety systems shut the flame off to prevent carbon-monoxide exposure.

Solution: venting inspection, cleaning, or correction.

When to Try DIY — and When to Call a Pro

Safe DIY steps include:

• Relighting the pilot following the manufacturer’s instructions
• Checking for drafts
• Vacuuming dust from around (not inside) the heater cabinet
• Ensuring the heater’s access panel is secured

DIY is safe if:

• No gas smell is present
• The pilot usually lights but occasionally goes out
• The unit is newer and previously reliable

Call a Professional Immediately if:

• The pilot keeps going out after relighting
• You smell gas
• The system shuts down repeatedly
• The furnace lights but immediately shuts off
• You hear unusual noises
• You see soot, rust, or moisture
• The system is older than 12–15 years

Honest Fix services wall heaters and furnaces across all 10 cities.

How Much Repairs Usually Cost

Pilot-Light Related Repairs:

• Pilot cleaning: $89–$190
• Thermocouple replacement: $175–$325
• Flame sensor cleaning/replacement: $129–$350
• Gas valve replacement: $350–$750
• Venting corrections: $150–$600

If Your Furnace Needs to Be Replaced:

Installed furnace ranges:

• Good: $4,200–$4,600
• Better: $5,400–$6,050
• Best: $5,700–$7,175**

Financing Options:

• 0% for 18 months
• 9.99% for 78 or 132 months
• 0% for 12 months on service repairs

These options help homeowners across the Ohio Valley get safe heat quickly.

Repair or Replace for Older Wall Heaters & Furnaces

Repair makes sense if:

• The unit is under 10–12 years old
• The issue is minor (sensor, thermocouple, pilot)
• The heat exchanger is in good condition

Replacement makes sense if:

• The unit is 12–20+ years old
• Multiple components are failing
• Venting is outdated
• The heat exchanger is cracked
• The pilot issue keeps returning

Wall heaters age faster due to dust and location, making replacement a common long-term fix in older homes.

The Guarantees That Protect You

Service Trust Guardian (Repairs)

• 5-year labor warranty
• 60-day satisfaction support
• No-overtime guarantee
• Clean-work-area guarantee
• On-time arrival credit

Lifetime Trust Shield (Replacements)

• 15-year labor warranty
• 90-day money-back protection
• No-lemon policy
• Energy-savings guarantee
• Price-match guarantee

These guarantees are designed to protect homeowners across all 10 service cities.

Frequently Asked Questions

Why does my pilot go out repeatedly?
The most common causes are dirty pilots, thermocouple issues, or drafts.

Is it dangerous if my pilot won’t stay lit?
It can be. Repeated failure may indicate CO or gas-related risks.

Why does my furnace light and then shut off?
This is usually a flame-sensor issue.

Can Honest Fix repair wall heaters?
Yes. We repair both furnaces and wall heaters across all 10 cities.

Your Next Step for a Safe, Reliable Fix

If your wall heater or furnace pilot light won’t stay lit in Steubenville, Wintersville, Weirton, Toronto, Mingo Junction, Brilliant, Follansbee, Wellsburg, New Cumberland, or Colliers, Honest Fix can diagnose the problem and restore safe, reliable heat.

Call Honest Fix today for a free exact quote. Learn about our guarantees before you decide.