Triangle Tube water heater locks out intermittently without a clear pattern; sometimes resets and runs normally.

Safety: Repeated lockouts indicate an underlying issue that should be corrected, not ignored.

• 1. Record error history: Note any error codes shown when lockouts occur. This helps pinpoint the subsystem involved.
• 2. Tighten connections: With power off, inspect and gently tug on all plug-in connectors at the control board, sensors, gas valve, and blower. Reseat and secure as needed.
• 3. Clean flame sensor: Even a marginally dirty flame sensor can cause intermittent flame loss. Clean as described in ignition fault troubleshooting.
• 4. Monitor gas supply: If lockouts coincide with other gas appliance use, have a gas technician check supply pressure under load.
• 5. Professional diagnosis: If intermittent issues persist, a technician should perform detailed electrical and combustion tests and may replace the control board.