Generator Basics: Engine Block Heaters

In this part of our Generator Basics series, we’ll be breaking down some information on engine block heaters. We’ll also be answering the question, “What does a block heater do?” and offering insights on proper maintenance and upkeep.

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What Are Engine Block Heaters?

Engine block heaters, also known as engine pre-heaters and generator water jacket heaters, play a huge role in maintaining ideal starting temperatures to ensure optimized performance for diesel and natural gas generators. Standby generators, according to the NFPA 110 code regulations, need to be installed and maintained properly to ensure reliable performance. These regulations also state that critical generators must start and reach operating conditions within 10 seconds of a power outage.

Engine block heaters can help ensure a commercial generator meets operational standards. Using an engine block heater to help with generator upkeep can make it easier to avoid cold starts, which occur when the functions and components have difficulty starting up due to extreme winter temperatures.

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. 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. Browse our used generators to see what options we have for you.

What Does a Block Heater Do?

A generator engine block heater provides the primary function of warming up the engine block, specifically the water or hydraulic fluid, when a generator is not in use. Since generators are not typically used all the time, engine block heaters act as a useful tool to ensure that they will start and run smoothly when they need to be cranked up. Engine block heaters are often used to start up generators in an extremely cold environment or during a power outage. There are many added benefits to owning an engine block heater, such as:

Reduces engine wear: With engine temperature coolants 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 in the generator, creating air pollutants, wet-stacking conditions and black smoke in the environment. Engine block heaters help a generator reach optimized conditions almost instantly, limiting wear on the engine by burning fuel properly. This also helps to conserve fuel and allow for longer operating times.
Less stress on other systems: Cold weather affects batteries and makes it difficult for the generator to start due to reduced capacity. A cold start can significantly drain the unit’s battery system. Engine block heaters can prevent this issue with consistent heating.
Less time-consuming: It can take a long time to start up a cold engine. The circulated warm water from the generator coolant heater also ensures that it will start up quickly and effectively when it needs to perform. This also removes the need to do a warm up exercise for the generator to get it to ideal operating temperatures.
Reduces condensation in the engine: Engine block heaters keep your engine warmer than the surrounding temperature. This technique reduces the amount of water condensation from cold air that seeps into engine sump components.

Types of Block Heaters

There are many different types of natural gas and diesel engine block heaters for commercial generators that offer various uses and benefits. For example, some engine block heaters heat up the block while others heat the fluid. Additionally, some engine block heaters are separate devices while others are incorporated into the engine itself or immersed in fluid. Two of the most common types of exterior engine block heaters are:

Thermosiphon heaters: These heaters, also known as natural convection heaters, reach a higher coolant temperature than most pump-driven heaters — optimal for the coldest winter climates. Thermosiphon heaters are mounted compact engine heaters that help circulate coolant without complicated requirements. They also maintain fluid temperatures for reliable, smooth engine starts. These engine heaters provide consistent heating to reduce downtime and are useful in a wide range of heating applications.
Forced circulation: Forced circulation heaters are versatile and use a pump to circulate coolant. They often come with integrated controls and sensors or have screen monitors to show temperature. They adjust wattage according to fluid temperature changes, reducing energy and fuel consumption. Some newer forced circulation heaters also automatically deactivate or reflect on mechanical gauges if they sense common problems like leaks or air pockets. These heaters are great for quick installation and offer less wear and tear on the coolant system.

Maintaining Engine Block Heaters

Proper maintenance and sizing are key to ensuring your engine block heater operates correctly. Regularly checking your engine block heater is important to ensure the coolant is maintained and starts will be successful. With components like these, it’s critical to check that they are operating correctly and meeting regulation standards for safety and environmental impact. Here are some maintenance and cleaning tips to remember with your engine block heater.

Check the heater weekly and drain, clean and flush every two years.
Make sure there is no residue, dust or dirt buildup on the outside of the heater.
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.

Maximizing the performance of your engine block heater with consistent maintenance is critical to the longevity of your commercial or industrial generator.

The Takeaway

Now that you know more about engine block heaters, you might be wondering if they are worth installing. In addition to the potential energy savings for some heaters — forced circulation units being a prime example — they minimize the risk of overstressing your engine. Reducing energy consumption and battery usage can help your commercial generator last longer and work more effectively. Engine block heaters are beneficial to your generator and can offer peace of mind to anyone who lives in climates that experience severe cold weather.

With a generator coolant heater, you can feel confident that your generator will work when you need it most by eliminating cold start concerns and assuring compliance with NFPA codes.

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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