Conn. Agencies Regs. § 29-232-99
Each automatically fired hot water boiler shall be protected from over-temperature by two temperature-operated controls.
Each individual automatically fired hot water boiler shall have a safety limit control that will cut off the fuel supply to prevent water temperature from exceeding the maximum allowable temperature of 250°F at the boiler outlet. This water temperature safety control shall be constructed to prevent a temperature setting above 250°F.
Each individual hot water boiler or each system of commonly connected boilers without intervening valves shall have a control that will cut off the fuel supply when the water temperature reaches an operating limit, which shall be less than the maximum allowable temperature.
Conn. Agencies Regs. § 29-232-99