Generator Basics: Engine Block Heaters

In this part of our Generator Basics series, we’ll be breaking answering the question “what does a block heater do?” and offering insights on proper maintenance and upkeep.

What are Engine Block Heaters?

Also known as Water Jacket Heaters and Engine Pre-Heaters, engine block heaters are essential for maintaining ideal starting temperatures for your diesel and natural gas generators. NFPA regulation 110 calls for all critical mission standby generators be able to start and reach operating conditions within 10 seconds of power loss. This requires the engine coolant to be maintained at 100 to 120 degrees Fahrenheit, in order to avoid a dangerous cold start.

Most new generator sets come with a block heater as standard equipment. However, it is best to understand what considerations go into choosing the appropriately sized heater. Firstly, consider fluctuations in the ambient operating temperature. For example, the colder the air, the more powerful heater required. The amount of water for cooling and the overall surface area of the engine also play an important role. Normal heating situations may require 3 watts of power for every cubic inch of compression space, and colder applications may go up to 5 watts per cubic inch.

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  • Reduces Engine Wear: With the temperatures maintained between 100 and 120 degrees, the oil pressure is elevated enough to provide sufficient lubrication on startup to limit the metal on metal contact associated with a cold start.
  • Reduces Emissions: A cold engine does not run efficiently. Less fuel combusts, causing wet-stacking conditions and black smoke. The block heater allows optimal conditions to be reached almost immediately, properly burning fuel and limiting engine wear. This also conserves fuel for longer operating times.
  • Less Stress on Other Systems: Cold batteries have reduced starting capacity, and a cold start can significantly drain the unit’s battery system.

Maintaining Engine Block Heaters:

Proper maintenance and sizing are key to ensuring your engine block heater is operating correctly.

  • Check the heater weekly and drain, clean and flush every two years.
  • Avoid hard water.
  • Mix antifreeze properly to avoid scaling and weather-related hard starts.
  • Professionals recommend changing out rubber hoses every three years. Silicone-based hoses are preferable for higher heat applications.

The Takeaway:

Ultimately, there are several more aspects to Generator Engine Block Heaters to discuss. Such as the different types of heaters, their components, and where to purchase aftermarket heaters. Because we understand that this can be overwhelming, we are here to assist with any questions on this topic. Please feel free to call us with any questions!

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