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MEDIUM URGENCY

Heil 8 Flashes - Gas Heating Lockout

8 flashes

Gas heating lockout - will not auto-reset.

Brand: Heil (Also covers Tempstar, Comfortmaker, Keeprite, ICP, Day & Night, Arcoaire)  |  Equipment: Gas Furnace

What This Code Means

8 flashes on Heil/Tempstar/Comfortmaker means the control has locked out gas heating after repeated ignition failures. Won't auto-reset - requires power cycle and underlying fix.

Likely Causes (Ranked)

Most common

Dirty flame sensor

What: Sensor can't detect flame.

How to check: Pull and inspect.

Fix: Clean with emery cloth.

Shop parts
Common

Failed igniter

What: Igniter not heating.

How to check: Watch for orange glow.

Fix: Replace.

Shop parts
Common

Gas valve issue

What: Valve not opening or closed manual valve.

How to check: Verify shutoff open; tech valve test.

Fix: Open shutoff or replace valve.

Shop parts

Diagnostic Steps

  1. Cut power 60s to clear lockout
  2. Watch heat cycle
  3. Clean flame sensor
  4. Replace igniter if no glow
  5. Verify gas supply

Frequently Asked Questions

How to clear Heil 8 flashes lockout?
Cut power 60s. Lockout clears, but underlying ignition problem must be fixed.
Most common fix?
Flame sensor cleaning.
Same on Tempstar/Comfortmaker?
Yes.

Related Heil Codes

Heil Error Code 6 Flashes

Related Symptoms

Furnace Not IgnitingFurnace Clicking Not Igniting

Need More Help?

Try our interactive symptom diagnostic tool or browse Heil parts.

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