The Holby Valve Company offers the first and most-widely specified water tempering valve in the industry. THE HOLBY TEMPERING VALVE is a temperature regulating valve, designed to be used as a master, zone, fixture or individual appliance regulator to control the predetermined temperature of hot water. Water delivered from hot water generating equipment such as storage tanks, heat exchangers, submerged coils, or any other source, is frequently too hot or scalding. This condition can be corrected by the installation of a HOLBY TEMPERING VALVE. It is a necessary part of any submerged tankless water heating system.