Flame Out Protection is a safety feature that will cut gas the supply immediately due to low propane pressure or burner malfunction. Automatic Fan Monitoring cuts gas supply should the air flow or combustion air supply be interrupted. Scald Protection is managed through an internal high temperature kill switch to protect against a thermostat malfunction. Model: ST-42 Flame Out Protection is a safety feature that will cut gas the supply immediately due to low propane pressure or burner malfunction Automatic Fan Monitoring cuts gas supply should the air flow or combustion air supply be interrupted Scald Protection is managed through an internal high temperature kill switch to protect against a thermostat malfunction