Ruud U802VA050317MSA Error Code A115_F: One-hour Lockout: Gas Valve Stuck Closed
What Does Code A115_F Mean?
Code A115_F on the Ruud U802VA is a one-hour lockout for a gas valve that is stuck closed. During a heat call the Bluetooth Communicating IFC energizes the gas-valve relay to open the valve, then confirms combustion through its flame sensor. In this fault the control has sent the open command but the valve does not respond as commanded, and at the same time the board detects voltage on the gas-valve circuit that it does not expect — a mismatch between what the control is commanding and what it measures on the valve terminals.
The U802VA IFC monitors its own gas-valve output as a safety check, so an unexpected voltage reading combined with a non-responding valve points to a specific set of failures: a gas valve whose internal coil or mechanism has failed so it will not open, or a control-board relay that is not switching the valve circuit cleanly. Because the valve never opens, the burners never light, and the furnace locks out rather than continuing to command an unresponsive valve.
This code sits at the opposite end from the undesired-flame faults on this board. Where A014_F, A127_F, and the A116_F lockout involve flame present with the valve commanded off, A115_F is the reverse: the valve is commanded open but stays closed. It also differs from A126_F, where the valve does open but no flame is sensed. The furnace will retry after the one-hour lockout, but a genuine valve or relay failure will simply recur until it is repaired.
What You'll Notice
- The contractor app or IFC shows A115_F and the burners never light during a heat call
- The furnace goes through its pre-ignition sequence (inducer, igniter) but produces no flame or heat
- No warm air from the registers despite the thermostat calling for heat
- The furnace tries again roughly an hour later and locks out the same way
- The inducer may run and then shut down without the burners ever igniting
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Faulty gas valve | Most common | ✗ Call a pro → |
| Control board relay issue | Common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms the valve is genuinely not opening on command rather than a downstream ignition problem, then measures the voltage the board is sending to the gas-valve terminals against what the valve is actually doing — the unexpected voltage that persists or disappears with the inducer helps localize the fault. From there they determine whether the gas valve itself has failed to actuate or whether the control board's gas-valve relay is not switching the circuit properly. Testing the gas valve, its wiring, and the IFC's gas-valve relay is diagnostic work on gas and control-board components and is informational only — it is not a homeowner repair.
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:
- A115_F is present and the burners will not light even though the furnace attempts to start
- The furnace locks out, retries after about an hour, and locks out again the same way
- There is any smell of gas near the furnace, in which case leave immediately and call your gas company first
- The furnace produces no heat and the fault stays active after power is cycled
Frequently Asked Questions
Does A115_F mean gas is leaking into my furnace?
No — this code is the opposite. The valve is stuck closed and not opening on command, so the burners never light. It is still a fault that stops the furnace from heating and needs a technician, but it is not an uncommanded-flame or gas-flow condition.
Why does the code mention unexpected voltage if the valve won't open?
The control monitors its own gas-valve circuit. Seeing voltage it does not expect, together with a valve that does not respond, is how the board distinguishes a stuck valve or a misbehaving gas-valve relay from a normal no-heat condition. A technician uses that signal to locate the fault.
Will the furnace fix itself after the one-hour lockout?
It will retry, but if the gas valve or the board's relay has actually failed, it will lock out again. The underlying part needs to be tested and likely replaced before the furnace will heat reliably.
✓ Verified against manufacturer service manual — March 2026