Like any other large equipment, it is essential that even diesel generators are operated at an optimal temperature. However, that is often not the case.  In most cases, diesel engines operate at sub-optimal temperatures to a large extent. Some cases are even worse, where the engine simply never reaches the ideal operating temperature. All of this results in excess fuel in the exhaust system, which in conjunction with carbon deposits leads to wet stacking. 

What is Wet Stacking?

Diesel engine generators work on the principle of burning diesel to create electric energy. Generators are often used as a backup source of power during outages. The diesel engine is primarily designed to make use of hot compressed air to vaporize and burn the fuel completely, which can happen only when the temperature is high enough. Under optimal conditions, a diesel generator usually functions reliably, offering ideal performance levels. 

Unfortunately, when the generators are used for less than the desired load, the generator fails to reach the ideal operating temperature. This results in defying internal friction. Moreover, it leaves behind a lot of fuel. All these combined make the generator ooze a thick dark liquid from its exhaust pipe. This thick, black, engine-oil-like sticky fluid is known as wet stacking. 

Wet Stacking of a generator
Wet Stacking of a generator

Causes of Wet Stacking

Some of the most prominent causes of wet stacking include –

  • Using the diesel generator at a sub-optimal temperature
  • Operating the generator at less than 60% of its rated power load
  • Incorrect air-to-fuel ratio 
  • Not using the generator for long stretches of time
  • Using a generator with too much or too little fuel

Signs of Wet Stacking

One of the easiest ways to spot the signs of wet stacking in your diesel generator is to check the exhaust pipe for any black-colored liquid. Yet another way to recognize wet stacking is to notice if there is black smoking coming out on a regular basis. 

The fuel buildup caused as a result of wet stacking can lead you to hear a miss in the engine when it is in use. This should also be treated as a sign of wet stacking.

Impact of Wet Stacking on the Diesel Generator

It shouldn’t come as a surprise that wet stacking adversely impacts the functioning of your generator. One of the most unfavorable effects of wet stacking is that the removal of unburned fuel from the combustion chamber causes a build-up in the exhaust system. Wet stacking also fouls the injectors with carbon deposits, causing the injector to deliver larger than ideal fuel droplets to the combustion cylinders. This causes an even larger amount of fuel to remain unburned. Moreover, it also leaves the exhaust pipes, turbocharger, and exhaust valves in a bad shape.  Simply put, wet stacking causes more wet stacking, and fast becomes a vicious circle that is difficult to break out of. 

The unburned fuel results in the accumulation of carbon deposits. These deposits combined with the overall exhaust buildup adversely affect the engine’s performance due to the excessive back pressure. The carbon deposits also reduce the efficiency of the turbocharger. 

Next, if the diesel generator constantly operates under the set temperature, the piston rings are unable to expand such that they can seal the gaps between the pistons and cylinder walls. These gaps enable the unburned fuel to reach the oil pan and dilute it – causing the overall wear and tear of the engine. 

Prevention of Wet Stacking

Wet Stacking of a generator

When it comes to wet stacking, prevention is much much better than cure. Why? Simply because repairs aimed at rectifying wet stacking can prove to be exceptionally expensive. Besides, wet stacking results in further wet stacking – which can lead to quick and lasting deterioration of the generator. 

Some of the most reliable measures for the prevention of wet stacking include the -

  • Operating the generator once every few days
  • Using the generator with an electric load that helps it reach the recommended temperature
  • Ensuring scheduled and preventative maintenance of the generator 

If you weren’t aware of these prevention measures, chances are that your generator is already suffering from wet stacking. In that case, all you need to do is get in touch with a reliable generator dealer and maintenance service provider like PowerGen Enterprises, and let an expert take over. 

Why Power Generation Enterprises?

At PowerGen Enterprises, we understand the importance of a generator that offers reliable performance. Hence, we have on board a select group of generator maintenance experts. To further help matters, we offer scheduled maintenance services for your generators, whereby our experts thoroughly inspect your generator and guide you on ways to prevent issues like wet stacking.

All in all, our experts ensure that your generator is in top condition at all times, so that you can rely on this robust equipment when the need arises. 

Frequently Asked Questions About Wet Stacking in Diesel Generators

Can Wet Stacking adversely affect a Diesel Generator?

Unfortunately, yes. Wet stacking can severely impact the functioning of a diesel engine generator, especially when it isn’t taken care of for an extended time period. Right from reduced engine performance to permanent engine damage – wet stacking almost always results in the need for a high-cost engine overhaul. 

Why should wet stacking be addressed on time?

Wet stacking, once occurred, can result in the building of immense pressure on the exhaust system of a generator. This, in turn, results in lasting damage to the diesel engine. When not addressed on time, wet stacking poses the need for expensive repairs and replacement. Even then, one cannot be sure of regaining the full efficiency of the generator. Hence, even if wet stacking isn’t prevented, it should be rectified well within time to mitigate the damage. 

What is the best way to prevent wet stacking?

The most reliable way to avert wet stacking is to ensure that the diesel generator operates at an optimal load. Moreover, making sure that the generator operates at maximum temperature is important, because it will help the fuel burn completely.