Diesel generators provide reliable power in various settings, from industrial sites to commercial backup systems. However, these machines can encounter issues that impact their performance and longevity, one of the most common being wet stacking. If not addressed, this condition can significantly reduce a diesel generator’s efficiency over extended periods and lifespan.
What is Wet Stacking?
The term wet stacking means the effect of unburned fuel accumulating in the exhaust system of diesel engines. This unburned fuel combines with soot and oil vapours, resulting in a thick, sticky residue buildup. If allowed to sit for a long period, this residue can cause various issues, including reduced engine performance, increased emissions, and potential damage to the generator.
Causes of Wet Stacking and Solutions
Wet stacking is typically caused by operating a diesel generator under light loads or for extended periods at low operational temperatures.
However, several factors contribute to this condition:
Running at Low Load
Diesel generators are designed to operate at optimal efficiency when running at or near their full load capacity. When a generator consistently runs at a low load (typically below 30% of its rated capacity), it does not reach the necessary operating temperature, leading to incomplete fuel combustion. This incomplete combustion results in unburned diesel fuel entering the exhaust pipes and system, causing wet stacking. To prevent this, aim to operate the generator at 70% of its rated capacity or above.
Frequent Short Runs
Running a generator for short periods without allowing it to reach its optimal operating temperature can contribute to wet stacking. Short runs prevent the engine from burning off the unburned fuel and accumulated soot, leading to a buildup over time. Aim to only operate the generator when you are able to run it for the intended length, to ensure the engine can reach the goal temperature.
Cold Ambient Temperatures
Operating a diesel generator in cold environments without adequate pre-heating can exacerbate wet stacking. Cold temperatures make it harder for the engine to reach the required operating temperature, increasing the likelihood of incomplete fuel combustion. This is why it is recommended to pre-heat the engine in cold weather.
Improper Maintenance
A poorly maintained generator may not operate efficiently, leading to incomplete combustion and increased wet stacking risk. Neglecting regular maintenance, such as oil changes, fuel system inspections, and air filter replacements, can contribute to wet stacking.
Using Low-Quality Fuel
Low-quality or contaminated fuel can burn less efficiently, leading to incomplete combustion. Using fuel that meets the manufacturer’s specifications is essential to prevent wet stacking.
Effects of Wet Stacking
Wet stacking can decrease the efficiency of your generator, as the engine struggles to burn off accumulated fuel and soot. This inefficiency can lead to higher fuel consumption and increased operational costs.
The buildup of unburned fuel in the exhaust system results in higher emissions of harmful pollutants, such as carbon monoxide (CO), hydrocarbons (HC), and particulate matter. This can lead to non-compliance with environmental regulations and contribute to environmental pollution.
Over time, wet stacking can cause significant damage to the engine components. This damage can lead to costly repairs or even complete engine failure if not addressed promptly.
Continuous operation under wet stacking conditions can significantly shorten the lifespan of your diesel generator, leading to premature replacement and hire costs.
Contact us to see what we can do to help you maintain or repair your generator.
Anna Eyre
Digital Marketing Lead
Share:
