what’s the difference?
If your operation is like most, you run your standby generator on a weekly basis, but you do so either unloaded or under loaded. Depending on the occasional utility loss to undertake this testing can result in a situation known as “wet stacking,” particularly with generators that are driven by a diesel engine.
During wet stacking, when the generator is under loaded, unburned fuel builds up in the engine’s exhaust system. The problem is that running your generator for short bursts of time under such conditions does not allow the engine to reach its optimum operating temperature.
Over time, as the unburned fuel continues to accumulate, the engine’s efficiency can be negatively impacted and its lifespan reduced.