Rheem R802VA07542117MSA Error Code A093_F: Internal Control Fault Detected

What Does Code A093_F Mean?

Fault code A093_F on the Rheem R802VA means the Integrated Furnace Control has detected an internal fault condition serious enough to trigger a hard lockout — the furnace will not attempt to restart on its own; power must be cycled only after the underlying cause has been addressed. Unlike sensor or wiring faults tied to a specific external part, A093_F is the IFC reporting a problem with itself.

One specific trigger the board watches for is voltage on the gas valve contacts that persists even when the inducer motor is shut off, which normally should not happen. That pattern points toward a welded relay on the board — a relay whose contacts have fused together in the closed position and can no longer be opened by the control's own commands. This is the same underlying mechanism described more specifically by A225_F, Internal Fault: Gas Vlv 1 Rly Welded Shut, and A227_F, Internal Fault: Gas Vlv 2 Rly Welded Shut, for the R802VA's two-stage gas valve relays. Where those two codes identify exactly which numbered relay is stuck, A093_F can appear as the board's broader internal-fault report around the same underlying condition or from other internal causes the self-diagnostics cannot pin down to one specific circuit.

Because the fault may reflect a relay that cannot reliably shut off the gas valve, or another internal electronic failure entirely, A093_F is treated as a hard-lockout safety condition rather than a routine glitch. Power surges, long-term component wear, or a manufacturing defect in the board's electronics can all produce this kind of failure, and the self-diagnostic system does not always distinguish between causes cleanly enough to name one.

There is no Bluetooth reprogramming step that resolves A093_F, because the fault is not a missing configuration — it is a hardware condition on the board itself, which is why board replacement is the most likely outcome once a technician confirms the fault.

What You'll Notice

• The furnace shuts down completely and will not restart on its own after this code appears
• The alphanumeric display shows A093_F
• The furnace does not respond to a normal power cycle attempt
• The lockout can occur during normal operation with no obvious external trigger like a dirty filter or blocked vent
• The fault may recur quickly after a reset if the underlying board condition is still present

Common Causes

How This Is Diagnosed

A technician first treats A093_F as a potential gas-valve-relay condition and checks whether voltage remains on the gas valve circuit with the inducer off, which would indicate a welded relay similar to what A225_F or A227_F describe more specifically. If gas valve voltage is not the trigger, the technician looks for other signs of internal board distress, such as evidence of a recent power surge or visible board damage, though the self-diagnostic fault code itself does not always point to one exact component.

Because this fault is generated by the board's own internal monitoring and is not tied to an external, replaceable sensor, there is limited value in a technician replacing the flame sensor, pressure switches, or other outside components in response to A093_F alone — the diagnostic path centers on the control board itself.

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 display shows A093_F and the furnace has entered a hard lockout
• There is any suspicion of a welded gas valve relay, since this can leave the gas valve unable to be shut off by the control
• A power cycle does not restore normal operation
• The furnace has experienced a recent power surge or outage before this fault appeared

✓ Verified against manufacturer service manual — March 2026