HVAC Code Lookup

American Standard Furnace Code E09

Soft lockout

The inducer limit switch or the condensate pressure switch is open. On a condensing furnace this most often means condensate is backing up.

Manual wording: “Open Inducer Limit Switch or Condensate Pressure Switch”

Documented for: A951X single-stage condensing furnaces

Likely causes, most common first

  1. Open inducer limit switch or condensate pressure switch
  2. Blocked condensate drain, trap, or hose
  3. Frozen condensate in a drain line running through a cold space
  4. Full or failed condensate pump
  5. Inducer overheating

What you can safely check yourself

  • Check the condensate drain line and trap for a clog
  • Check that any condensate pump is plugged in, not full, and pumping
  • In freezing weather, check whether any part of the drain line runs somewhere cold enough to freeze

When to call a technician

If the drain and pump are clear, the inducer limit or condensate switch needs a technician. Do not bypass either switch.

A American Standard furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Source

Other American Standard codes