As a generalized category of ...

As a generalized category of carryover, I have always related it to be caused by the following but no exclusively to:

• Operational - If a boiler is not properly brought up to pressure and ready to meet the steam demand, priming can occur. 
  Mismanagement of COC's by over cycling and lead to carry over.
• Mechanical - If there are malfunctioning high level sensors or ancillary steam/heat exchanger components causing an imbalance in back pressure then vacuum, carryover can occur.
• Contaminants - F.O.G. ~ Fats, Oils and Greases being returned in the condensate and subsequently entering into the DA will ultimately enter into the boiler. The increased surface tension, similar to the over cycling of the boiler water, will lead to carryover.

The impact, to name a few, will cause:

• System failure
• Unreliable performance
• Contaminated/wet steam ~ leading to insufficient heat exchange
• Product contamination in cases of direct steam contact operations.