Lennox Ducted Heating

Lennox Error Code 4 flashes

Ducted Heating:

What It Means

  • Before ignition: Hi limit CLOSED? NO: check main valve OFF; hold until hi limit closes. During operation: rollout CLOSED? NO: lockout main valve OFF, combustion/system fans ON; reset or replace rollout switch. During operation hi limit CLOSED? NO: main valve OFF, combustion/system fans ON; hold until switch closes. These three conditional branches are separate.

Causes & actions from Lennox

How it shows
  • ram diagnostic led: 4 flashes

Hi limit switch or rollout switch open. Sequence holds until switch closes, or lockout occurs on rollout switch trip.

Applicable models & manual sources
  • G24M

    Before ignition: Hi limit CLOSED? NO: check main valve OFF; hold until hi limit closes. During operation: rollout CLOSED? NO: lockout main valve OFF, combustion/system fans ON; reset or replace rollout switch. During operation hi limit CLOSED? NO: main valve OFF, combustion/system fans ON; hold until switch closes. These three conditional branches are separate.

    G24M manual, page 24

Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.

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