The NF15/9L is a high reliability temperature and flame controller system from Honeywell. It is a self-monitoring solid state unit that consists of a flame signal processor, temperature controller, a fuel valve monitor and a flame proving device. The NF15/9L is designed to provide safe and efficient furnace operation by detecting any dangerous conditions before they become a problem. The system is compatible with natural gas, propane, oil, wood, and coal fuel sources. The NF15/9L is designed to provide complete safety protection, optimal combustion performance, temperature and flame control and easy installation.