Balance tanks have become an equipment which is preferred more especially by means of the popularity of the cascade systems in today. Balance tank is an equipment which protecting the heat balance against the stress caused due to the heat loss occurring while the fluid within the heating facility is returning from the facility to the tank, and allows balanced environment by mixing the cooled water incoming from the facility with hot water incoming from the tank. Moreover, temperature can be checked with sensors installed on the balance tanks. It increases the performances of tank systems (cast steel tanks), cascade systems, various air conditioning systems, and provides savings and extends the tank life by preventing thermal stress.