If water inside boiler is not finished very well in spite of its preparation phase, density of insoluble materials (TDS) will be increased because of steam producing. It will cause harm to boiler and pipeline if determined limits is passed. These harms cause errors to equipment. Insoluble materials are dragged with steam and they can increase the conductibility of condensate and cause energy loss. The insoluble material-generally calcium and magnesium salts- consists during the steam producing and it is removed by some techniques for optimum TDS level. This operation is called BLOWDOWN.