How to Avoid Wet Stacking in Diesel Generators

Diesel engines power generators for backup power systems. There are many benefits to using diesel generators, but doing so properly is vital for avoiding issues like wet stacking, which can reduce engine performance and cause your backup power system to shut down. Understanding what wet stacking a generator is and how to avoid it is vital for running your backup power system correctly and efficiently.

What Does Wet Stacking a Generator Mean?

Wet stacking describes when diesel engines are not operated correctly and do not run at the correct operating temperature. This issue causes a buildup of a dark, congealed liquid that consists of unused diesel fuel, carbon particles, and moisture in the exhaust system, which gives wet stacking its name.

What Causes Wet Stacking?

Wet stacking can happen for several reasons, with the primary issues including:

• Operating the diesel generator with little load for extended periods of time.
• Running a generator at less than 40% of its rated capacity for extended periods of time.
• Using the generator under its set operating temperature.
• Running the generator using too little or too much fuel.
• Using the wrong fuel for your generator.
• Powering the diesel generator with the incorrect air-to-fuel ratio.

What Are The Signs of Wet Stacking a Generator?

The most noticeable sign of wet stacking is a thick, black liquid soot leaking out of the generator’s exhaust system or wet deposits on the exhaust system’s components, such as the exhaust pipes and manifold. If the generator has turbochargers, you may also see a buildup around them. You may initially confuse the liquid with lubricating oil because of its density, but the sooty black color clearly indicates wet stacking due to the unburnt carbon particles.

Other signs of wet stacking include continuous black exhaust smoke and reduced performance and efficiency.  Wet stacking also degrades exhaust emissions and can cause pollution. There are restrictions on wet stack smoke emissions and significant fines associated with them.

The Impact of Diesel Engine Wet Stacking

Wet stacking can be highly problematic for your generator’s performance. More significantly, wet stacking can shorten the engine’s life span and increase maintenance costs. It can also lead to a complete shutdown, and if severe enough, it can cause expensive repairs and replacements.

How to Avoid Wet Stacking

Thankfully, these measures for how to avoid wet stacking in diesel generators are highly effective:

• Operate at optimal load levels: It is a good practice to run your generator at at least 60% load once per week. If you are already experiencing wet stacking, you can try running the generator at 75 to 100% for a couple of hours to burn off the deposits.
• Use high-quality fuel: Choose quality fuels with appropriate cetane ratings to ensure complete combustion and no leftover deposits. Generally, diesel engines operate efficiently with a cetane rating of 48 to 50. Fuels with lower cetane numbers have larger ignition delays and take longer to burn completely — which may lead to wet stacking.
• Implement monitoring and diagnostics: Exploring remote monitoring for diesel generators can help you manage fuel consumption and efficiency and eliminate issues like wet stacking. With the right technology, you can ensure your generator remains in optimal condition without being on the premises.
• Ensure regular maintenance: Performing regular maintenance on your generator is essential for ensuring performance, extending its life span, and maximizing your investment. Regular maintenance involves thorough inspections and oil and filter changes that can help avoid wet stacking.

About Thompson Tractor

At Thompson Power Systems, we provide robust mobile diesel and gas generator sets to suit your specific backup power requirements. We have an extensive range of equipment, including new, used and rental options. With over 65 years of experience providing critical power solutions to businesses in Alabama and Northwest Florida, we can help your operations run smoothly. You can also rest assured that we are dedicated to offering the best Cat^® generators and power systems on the market.

Quality Generators and Excellent Services With Thompson Power Systems

Contact Thompson Power Systems for all your backup power needs, including comprehensive generator maintenance services, load bank testing, and repairs. We can discuss tailored solutions that keep your business running despite the challenges you may face with power supply. We cater to a variety of different needs, industries and budgets with our mobile generator options, microgrids, and renewable systems.