Ruud U802VA050317MSA Error Code A115_F: One-hour Lockout: Gas Valve Stuck Closed
What Does Code A115_F Mean?
Fault code A115_F on the Ruud U802VA indicates a one-hour soft lockout triggered by detection of unexpected voltage on the gas valve circuit. The specific trigger is voltage going away on the gas valve connections when the inducer is shut off — a condition the IFC does not expect during normal operation.
On the U802VA, the IFC monitors the gas valve circuit and will flag unexpected voltage conditions as a safety measure. Detecting voltage on the gas valve when the inducer has been turned off points to either a gas valve that is generating back-voltage, a control board relay that is not fully releasing its contacts after receiving the open command, or a wiring issue that has connected an unintended voltage source to the gas valve terminal.
The furnace will automatically attempt to restart after the one-hour lockout expires, but if the root cause is not corrected, the fault will recur. The U802VA documentation confirms that power cycling can clear lockout conditions, but a recurring A115_F requires professional diagnosis of the gas valve and control board.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Faulty gas valve | Most common | ✗ Call a pro → |
| Control board relay issue | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Call a technician to inspect the gas valve circuit and control board relay before the furnace is restarted
- A technician should measure voltage at the gas valve terminals with the inducer off to confirm and diagnose the unexpected voltage condition
- If the fault recurs after the one-hour lockout, do not continue operating the furnace until the gas valve or control board relay has been evaluated
✓ Verified against manufacturer service manual — March 2026