Distilled water is water that has had many of its impurities removed through distillation. Distillation involves boiling the water and then condensing the steam into a clean container. Distilled water is also preferable to tap water for use in model steam engine boilers and model engines of other types.Mineral build-up resulting from the use of tap water in model boilers can severely reduce the efficiency of the boilers if run for long periods.
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