Why is water filtration important for steam equipment? Combi ovens are often the hardest working piece of kitchen equipment in a restaurant, often running 12 to 18 hours a day. Steam is 100% water and it can contain the same impurities as your water. Another problem happens when you heat water, causing minerals to come out of solution and form scale which will clog your equipment, which means downtime.Using filter cartridges for steam cooking will help reduce scale buildup and keep our cooking equipment up and running