According to the author's literal meaning, the diesel generator must be equipped with a water heater.
The water heater is a professional preheating device for diesel engine cooling water and lubricating oil. It is an essential supporting device for diesel engine drag equipment when the working environment may be below 4°C. When the operating environment may be lower than 4°C, during the start-up phase, the lubricating oil and cooling water of the engine may condense into a solid state and lose their lubricating or cooling functions, thus damaging the engine.
Generally, when the external ambient temperature is low, it is recommended to equip the diesel generator set with a water heater.