There is a hot well (see Figure (v)) that collects all the condensates from steam system end-users plus where water treatment and cleaning may take place. It is from hot-well that the feed water is supplied to the boiler. Hot well temperature must be maintained at temperature specified by manufacturers. A low temperature (e.g. below 80-85 C) will cause colder feed water to enter the boiler thus increasing the fuel cost due to the need for more heating for evaporation.
An overheated hot well may cause evaporation of water at the suction of feed pump (e.g. cavitation) and cause vapor lock in the feed pump and loss of suction. For heat retention in the hot well to keep temperature higher, heat losses due to poor insulation can be reduced. Also, control of make-up water is important as excessive need for make-up water will be indicative of leak in the steam system as well as more heating for make-up water that is normally at low temperature.
The blow down of the boiler is required for controlling the amount of dissolved solids as a result of evaporation and impurity of make-up water or addition of other chemical. Blow down must be calculated and done after measuring the level of dissolved water. In some cases, the engineers blow down the boiler excessively, thus not only loose hot water, but also increase the need for make-up water and make-up water generation.
