5 Flame sensed with gas valve off

What the control is telling you

The board sees flame while the gas valve should be closed. The inducer keeps running until the fault clears.

Applies to: KeepRite (F/G)9MXE single-stage and (F/G)9MXT two-stage 95% furnaces

Likely causes

• Gas valve stuck open or leaking through

Test and repair steps

1. Warning: shut off the manual gas valve if flame is present with no heat call.
2. Confirm the gas valve has no 24 V when no flame is expected.
3. Replace a gas valve that passes gas while de-energized.

Settings for these units

• Filter size by casing width · KeepRite (F/G)96VTN Two-Stage Variable-Speed Furnace

Models that show this code

16 models in KeepRite (F/G)9MXE Single-Stage Furnace, KeepRite (F/G)9MXT Two-Stage Furnace

Other codes on the same units

• 1+2 Blower running after power-up (normal)
• 2 Pressure switch stuck closed (did not open)
• 3 Pressure switch did not close or reopened
• 4 Limit or rollout circuit open
• 6 Flame not proved during ignition trial
• 6+1 Ignition lockout after 4 failed tries
• 7 Limit circuit lockout
• 8 Gas heating lockout - manual reset needed