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MEDIUM URGENCY

Heil 3 Flashes - Pressure Switch Did Not Close

3 flashes

Pressure switch did not close when inducer started.

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

What This Code Means

3 LED flashes on Heil/Tempstar/Comfortmaker/Keeprite furnaces mean the pressure switch failed to close after the inducer motor started. Indicates insufficient draft.

Likely Causes (Ranked)

Most common

Blocked exhaust vent

What: Snow, ice, debris in exhaust.

How to check: Inspect outdoor exhaust outlet.

Fix: Clear blockage.

Shop parts
Common

Failed inducer motor

What: Inducer can't create draft.

How to check: Listen at startup.

Fix: Replace inducer.

Shop parts
Common

Bad pressure switch

What: Won't close on proper pressure.

How to check: Tech test.

Fix: Replace switch.

Shop parts

Diagnostic Steps

  1. Check outdoor exhaust
  2. Listen for inducer
  3. Inspect tubing
  4. Replace switch if needed

Frequently Asked Questions

Most common cause?
Blocked exhaust vent, especially in winter.
Same on all ICP family brands?
Yes - Heil, Tempstar, Comfortmaker, Keeprite use the same codes.
DIY?
Vent clearing yes.

Related Heil Codes

Heil Error Code 2 Flashes

Related Symptoms

Furnace Not IgnitingFurnace Blowing Cold Air

Need More Help?

Try our interactive symptom diagnostic tool or browse Heil parts.

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