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Equipment error code

Lennox code E201

E201 — low flame signal. Flame was detected but below the minimum microamp threshold required to hold the gas valve open.

Equipment
furnace
Brand
Lennox
Source checked
2026-03-01

What this code means

E201 — low flame signal. Flame was detected but below the minimum microamp threshold required to hold the gas valve open.

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

Which models show it

Lennox SLP98V, EL296V, SL280V, ML193, and compatible furnaces reporting numeric E-codes on display or iComfort.

What is actually happening

Burners may light weakly then shut off, or never stay lit long enough to heat. The board drops flame proof and logs E201.

Is it safe to keep running?

Avoid repeated heat calls. Weak flame can produce carbon monoxide — ventilate if you smell exhaust.

Shut it down when

Yellow or floating flames, soot, or E201 more than twice after one reset.

What a homeowner can safely check

  • Confirm gas shutoff is on and other gas appliances work.
  • Replace a heavily soiled filter.
  • Ensure combustion air grilles are not blocked in utility rooms.
  • Power cycle once after checks — not repeatedly.

When to stop

  • Gas odor.
  • Visible soot or discoloration at burners.
  • E201 returns within one cycle.

Likely causes ranked

  1. 1. Dirty or misaligned flame sensor

    How a tech confirms: Microamp test; cleans and positions rod per Lennox spec.

    Typical repair: $155–$340 · Air Conditioner Repair cost guide

  2. 2. Low gas pressure or meter issue

    How a tech confirms: Manometer at valve; coordinates with utility if supply-side.

    Typical repair: $180–$450 · Air Conditioner Repair cost guide

  3. 3. Weak igniter or delayed ignition

    How a tech confirms: Ignition timing observation; replaces HSI if out of range.

    Typical repair: $210–$490 · Furnace Replacement cost guide

  4. 4. Cracked heat exchanger causing flame disturbance

    How a tech confirms: Heat exchanger inspection; combustion spillage test.

    Typical repair: $3,600–$7,900 · Furnace Replacement cost guide

Is this the end of this unit?

E201 with confirmed exchanger damage means furnace replacement — flame signal fixes alone will not make a cracked chamber safe.

How to clear the code

Single power cycle after gas and filter checks. Wait five minutes before a new heat call to allow purge timers.

Why clearing is not fixing it: Low microamps return whenever the sensor, gas pressure, or combustion path is still marginal.

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 does Lennox E201 mean?
Low flame signal — the board saw flame but not enough electrical proof to keep the gas valve open.
Is E201 the same as no ignition?
Close — sometimes flame starts then drops. Carrier code 13 is a total no-flame trip; E201 is weak flame proof.
Can I clean the flame rod for E201?
Possible on some units, but gas and high voltage are nearby — many homeowners use a technician.
E201 repair costs?
$155–$490 for sensor, gas, or igniter work; exchanger failure leads to $3,600+ replacement.
Does iComfort show E201 history?
Many iComfort setups log recent faults — note the code for your HVAC tech before it clears.

Source

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