Water heater intermittently shuts down with 'Soft Lockout' indicated; unit may restart automatically after a delay or after a manual reset.

Safety first: Turn off power and gas before opening the burner or control compartments.

• Record the fault: Note any error description or LED blink code associated with the Soft Lockout. This helps identify whether the issue is ignition, flame loss, or temperature related.
• Check venting and air intake: Inspect PVC or metal vent and combustion air intake pipes for blockages (leaves, nests, ice, debris). Ensure terminations are clear and properly spaced from walls and other structures.
• Verify gas supply: Confirm the manual gas valve is fully open. If other gas appliances show issues, contact your gas supplier. Low pressure can cause intermittent flame loss.
• Clean flame sensor: Remove the flame sensor rod and gently clean it with fine steel wool or emery cloth. Reinstall, ensuring the ceramic insulator is intact and the rod is fully in the flame path.
• Inspect condensate drain (for condensing models): Check the condensate trap and drain tubing for clogs or kinks that could affect combustion chamber pressure. Clear any blockage and refill the trap with clean water.
• Reset and observe: Restore power and gas, reset the control, and observe at least one full ignition cycle. If Soft Lockouts continue, schedule service; the gas valve or control board may require testing and calibration.