Replace a faulty thermostat on your Hi-Flame Precision 3 boiler stove with this genuine spare. The Precision I (HF905)I (HF907)I (HF910) Boiler Thermostat controls water temperature in the boiler system and is essential for safe, efficient operation. This replacement is made to the original specification for the Precision 3. Installation should be carried out by someone familiar with boiler stove systems.