Lennox Error Code 7: Ignition Lockout

Severity
Warning
Type
led blink count
Where to look
sight glass
Estimated repair cost: $100 — $250 (parts + labor)
Warning: Your Lennox HVAC system has entered ignition lockout. It's safe, but needs professional attention.

LED Blink Pattern

How to Fix Lennox Code 7

  1. Check if your system has power. If not, reset the circuit breaker.
  2. Listen for any unusual noises from your furnace. If you hear any, call a professional.
  3. Do not attempt to open your furnace or tamper with any internal components.

How to Reset Lennox Code 7

  1. Turn off the furnace power switch, usually located on or near the unit.
  2. Turn off the circuit breaker for the furnace. Wait 30 seconds.
  3. Restore power at the breaker and flip the furnace switch back on.
  4. Set the thermostat to call for heat. If the error code returns after 2-3 ignition attempts, the fault requires repair.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Lennox Error Code 7 Mean?

Lennox error code 7, or ignition lockout, means your heating system has temporarily shut down to prevent damage. This could be due to a safety feature kicking in, or a minor issue that needs addressing. Don't worry, it's not a gas leak or fire risk, but it's best to get it checked out.

Common Causes

  • Safety feature activated due to high flame rollout or improper ignition
  • Faulty igniter or flame sensor
  • Clogged or dirty flame sensor
  • Incorrect gas pressure or flow

Diagnostic Steps

If... Check Expected
Furnace is not running Reset the circuit breaker Furnace should restart
Furnace runs but doesn't ignite Inspect the igniter and flame sensor No visible damage or dirt

Applicable Lennox Models

Replacement Parts

Part OEM Number Est. Cost Where to Buy
Igniter 65-598325-00
Flame Sensor 65-598326-00

Related Codes on Same Models

Other codes that affect the same Lennox model families as 7.

Code Description Severity
1 Ignition Failure Warning
2 Pressure Switch Stuck Closed Warning
3 Pressure Switch Stuck Open Warning
4 High Limit Switch Open Warning
5 Flame Rollout Switch Open Warning
6 Pressure Switch System Lockout Warning
8 Control Board Error Warning
9 Line Voltage Polarity Incorrect Warning
E250 Lennox Code E250 - Indoor Blower Communication Error Warning