Wet Stacking – What is it and how to prevent it?

Date Published: April 25, 2023

Wet Stacked Generator

Prime power generators are an essential part of many industries, providing backup power in the event of a power outage or serving as a primary source of electricity in remote areas. These generators are critical to ensuring the continued operation of businesses, hospitals, data centers, and other facilities that rely on uninterrupted power. However, prime power generators are subject to a common problem known as wet stacking. Wet stacking occurs when unburned fuel and oil accumulate in the generator’s exhaust system, creating a sludge-like substance that obstructs airflow and reduces engine performance. This buildup can cause significant damage to the generator over time, resulting in costly repairs or even the need for a replacement. Learning what causes wet stacking and how to prevent it is critical to ensuring that the site support equipment stands the test of time.

In this blog post, we will explore what wet stacking is, how it affects prime power generators, and what can be done to prevent it.

What is Wet Stacking?

Wet stacking is a term used to describe the accumulation of unburned fuel and oil in a generator’s exhaust system. This buildup can occur when a generator operates at low loads or is subjected to frequent starts and stops, which prevents the engine from reaching its optimal operating temperature.

When fuel is burned in a generator’s engine, it produces exhaust gases that are expelled through the exhaust system. However, if the engine is not operating at its optimal temperature, these gases can condense and mix with oil in the exhaust system, forming a thick, sticky substance known as wet stack.

The formation of wet stack can cause several problems for prime power generators. Firstly, it reduces engine performance and efficiency, leading to increased fuel consumption and decreased power output. Secondly, it can lead to increased emissions and environmental damage. Finally, wet stack buildup can cause significant damage to the generator over time, resulting in costly repairs or even the need for a replacement.

Statistics About Wet Stacking

To understand the scope of the wet stacking problem, let’s take a look at some statistics:

  1. Up to 60% of generator failures are caused by wet stacking.
  2. Wet stacking can reduce generator efficiency by up to 50%.
  3. A buildup of just 1/8 inch of wet stack can reduce generator efficiency by up to 10%.
  4. Generators operating at loads below 30% are at the highest risk for wet stacking.
  5. Wet stacking can cause a 15% increase in fuel consumption.

How Wet Stacking Affects Prime Power Generators

Wet stacking can have a significant impact on the performance and efficiency of prime power generators. The buildup of wet stack in the exhaust system can cause a reduction in engine performance,

leading to increased fuel consumption and decreased power output. Additionally, wet stack buildup can cause damage to the generator over time, resulting in costly repairs or even the need for a replacement.

Reduced Engine Performance

Wet stack buildup can cause a significant reduction in engine performance, leading to decreased power output and increased fuel consumption. As wet stack accumulates in the exhaust system, it obstructs airflow and reduces the efficiency of the engine. This can result in reduced power output and increased fuel consumption, as the engine works harder to produce the same amount of power.

Increased Emissions

Wet stacking can also lead to increased emissions and environmental damage. When wet stack accumulates in the exhaust system, it can cause incomplete combustion of fuel, leading to increased emissions of carbon monoxide, nitrogen oxides, and other harmful pollutants. This can have a significant impact on air quality and contribute to climate change.

Damage to the Generator

Finally, wet stack buildup can cause damage to the generator over time, resulting in costly repairs or even the need for a replacement. Wet stack can cause corrosion and damage to the exhaust system, as well as the engine itself. If left unchecked, wet stack buildup can lead to significant damage to the generator, requiring extensive repairs.

How to Prevent Wet Stacking in Your Generator

Fortunately, there are several steps that can be taken to prevent wet stacking and ensure the continued operation and longevity of your generator.

1. Load Bank Testing

One of the most effective ways to prevent wet stacking is through the use of a load bank, like the ones found standard on the Megagen Z-Series generators. Load bank testing involves simulating the full load of the generator, which helps to burn off any unburned fuel and oil in the exhaust system. This process ensures that the generator is operating at its optimal temperature and prevents wet stacking from occurring.

2. Regular Maintenance

Regular maintenance is critical to preventing wet stacking. This includes changing the oil and filters at regular intervals, checking and replacing air filters, and cleaning the exhaust system. Regular maintenance helps to ensure that the generator is operating at its optimal performance and reduces the risk of wet stacking buildup.

3. Proper Sizing

Ensuring that your generator is properly sized for the load it will be carrying is essential to preventing wet stacking. Generators that are oversized for the load they are carrying are more susceptible to wet stacking buildup, as they are operating at lower loads and temperatures. Proper sizing ensures that the generator is operating at its optimal temperature and reduces the risk of wet stacking.

4. Consistent Use

Consistent use of the generator can also help to prevent wet stacking buildup. Generators that are used consistently are less likely to experience wet stacking, as they are operating at their optimal temperature more frequently. Consistent use also helps to prevent the buildup of moisture in the exhaust system, which can contribute to wet stacking.

5. Fuel Quality

The quality of the fuel used in the generator can also have an impact on wet stacking buildup. Using high-quality fuel can help to prevent the buildup of unburned fuel and oil in the exhaust system, reducing the risk of wet stacking. Additionally, ensuring that the fuel is stored properly and free from contaminants can also help to prevent wet stacking.

6. Operating Conditions

The operating conditions of the generator can also impact wet stacking buildup. Generators that are subjected to frequent starts and stops or operate at low loads are more susceptible to wet stacking buildup. Ensuring that the generator is operated at its optimal load and temperature can help to prevent wet stacking.

Conclusion

In conclusion, wet stacking is a common problem that can cause significant damage to prime power generators over time. However, by following these steps, you can help to prevent wet stacking and ensure the continued operation and longevity of your generator. Regular load bank testing, maintenance, proper sizing, consistent use, fuel quality, and operating conditions all play a role in preventing wet stacking buildup. By taking these steps, you can help to ensure that your generator is operating at its optimal performance and reduce the risk of costly repairs or replacements due to wet stacking.

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If you’re interested in investing in site-support equipment designed specifically to prevent wet stacking, please contact us today to learn more or request a quote on our Megagen Z-series generators.