Skip to main content
True Trade Path

Equipment error code

Lennox code E225

E225 — low pressure switch open. The control did not detect closure of the low-pressure (draft proving) switch during the inducer pre-purge.

Equipment
furnace
Brand
Lennox
Source checked
2026-03-01

What this code means

E225 — low pressure switch open. The control did not detect closure of the low-pressure (draft proving) switch during the inducer pre-purge.

Source: Lennox EL296V Installation Instructions — Fault Code Table (EHB-EL296V-01) · checked 2026-03-01

Which models show it

Lennox SL280V, EL296V, ML193, SLP98V, and Merit series furnaces with electronic display or iComfort fault reporting.

What is actually happening

Inducer runs without advancing to ignition, or cycles off with E225 on the display. Heat is blocked until draft is proven.

Is it safe to keep running?

Heating is inhibited. Repeated retries wear the inducer without fixing venting.

Shut it down when

Exhaust odors, iced vents you cannot clear, or condensate leaking inside the cabinet.

What a homeowner can safely check

  • Clear intake and exhaust PVC terminals outdoors.
  • Check condensate trap and drain on condensing models.
  • Inspect rubber pressure tubes at the inducer — reconnect if loose.
  • Confirm furnace doors are latched.

When to stop

  • E225 after trap and vent service.
  • Unusual inducer noise or vibration.
  • Roof vent work needed.

Likely causes ranked

  1. 1. Blocked vent or combustion air intake

    How a tech confirms: Draft measurement and vent inspection per Lennox install manual.

    Typical repair: $190–$480 · Air Conditioner Repair cost guide

  2. 2. Failed low-pressure switch

    How a tech confirms: Vacuum test and switch replacement.

    Typical repair: $195–$410 · Air Conditioner Repair cost guide

  3. 3. Weak inducer assembly

    How a tech confirms: Amp draw, wheel inspection, OEM inducer replacement.

    Typical repair: $380–$900 · Furnace Replacement cost guide

  4. 4. Condensate backup in collector

    How a tech confirms: Drain flush, collector inspection on 90%+ units.

    Typical repair: $175–$425 · Air Conditioner Repair cost guide

Is this the end of this unit?

Repeated E225 on furnaces over 15 years with inducer and collector repairs over $1,000 favor replacement — especially if heat exchanger warranty has expired.

How to clear the code

Clear vents and condensate, latch doors, power cycle once at the disconnect. Wait for pre-purge before expecting ignition.

Why clearing is not fixing it: E225 clears when the switch proves draft. Without vent or switch repair, the fault returns on the next heat call.

Which trade to call

Call a licensed hvac contractor who works on furnace equipment. Gas, refrigerant, and combustion faults are not general handyman jobs.

Related codes and symptom guides

More codes from this brand

Symptom guide: Furnace Not Heating

FAQ

What is Lennox error E225?
Low pressure switch open — the furnace did not prove draft before ignition.
Where do I see E225?
On the furnace display or iComfort thermostat depending on model and communication setup.
Can condensate cause E225?
On high-efficiency Lennox furnaces, a full trap can prevent pressure switch closure.
Typical E225 repair cost?
$175–$480 for vent or trap service; $380–$900 for inducer replacement.
E225 vs Trane 2 flash?
Same draft-proving failure class — follow Lennox documentation for your exact control.

Source

Source — Lennox EL296V Installation Instructions — Fault Code Table (EHB-EL296V-01). Checked .