Rheem R802VA07542117MSA Error Code A127_F: Flame Present with Gas Valve Off - UL

What Does Code A127_F Mean?

Code A127_F describes the same physical event as code A014_F on this board — the flame sensor reads flame while Rheem's Bluetooth Communicating IFC has commanded the gas valve closed — but A127_F is the UL (Underwriters Laboratories) compliance-flagged form of that fault, raised through the control's safety-monitoring logic for gas ignition systems. Whether the furnace reports A014_F or A127_F for a given undesired-flame event, both point to the same underlying hazard on your two-stage, variable-speed R802VA07542117MSA: combustion appears to be happening when the control believes it shut the gas off.

A127_F is the mirror image of code A126_F elsewhere on this board. A126_F is gas valve confirmed open with no flame detected — an unburned-gas risk during ignition — while A127_F is flame detected with the valve supposed to be closed. It is also distinct from code A116_F, which is the formal one-hour lockout state built around this same undesired-flame condition; A127_F is the UL-flagged detection of the condition rather than the lockout-timer code itself.

The primary safety concern is a gas valve stuck open and continuing to supply gas after the 'off' command, or a control-board relay that has welded closed and keeps voltage applied to the valve regardless of what the IFC commands — the condition described by codes A225_F (gas valve 1 relay welded shut) and A093_F (internal fault, possibly a welded gas-valve relay). A faulty flame-sensing circuit giving a false positive is the other possibility. If the valve cannot be confirmed to close, gas can keep flowing during periods when the furnace should be completely idle, which is why this is treated as a critical UL fault and why the safe homeowner action is to shut the furnace off and close the manual gas supply valve until a technician has inspected it.

What You'll Notice

• The alphanumeric LED blinks out the A127_F fault code digit by digit, with a roughly 3-second pause between digits
• The furnace shuts down and stops responding to thermostat calls until it is inspected
• Burner flames may appear to keep producing heat briefly after the 'off' command before going out
• There may be a smell of gas near the furnace, or a burner still lit when no heat was called
• No further ignition attempts occur until a technician clears the fault

Common Causes

How This Is Diagnosed

A technician measures the flame-sense current with the gas valve commanded off to verify the flame condition is real rather than a false electrical reading, tests the gas valve's solenoid and coil to confirm it closes reliably, and verifies the actual voltage at the valve terminals against what the IFC has commanded, since this board monitors valve voltage directly.

If the valve itself closes correctly, the technician checks the control-board relay that switches it for welding — the condition behind codes A225_F and A093_F — because a welded relay keeps the valve powered no matter what the board commands and produces a genuine uncommanded flame. That is why a recurring A127_F is treated as a control and gas-train inspection rather than a simple sensor issue.

When to Call a Professional

This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:

• The code appears at all, since flame present with the valve commanded off is unsafe to diagnose without proper tools
• The code returns immediately after an attempt to restart the furnace
• Burner flames or heat continue after the furnace should be idle
• There is any smell of gas near the furnace
• The furnace recently had its control board replaced and the fault appeared afterward

✓ Verified against manufacturer service manual — March 2026