IBO ITALY domestic hot water expansion vessels are pressurized diaphragm vessels used in domestic hot water systems to stabilize pressure and compensate for the thermal expansion of water. They have a blue outer coating and are designed to operate in closed water systems at temperatures from approximately -10 to 100 °C (for short periods, up to 130 °C, for a maximum of 2 hours).
Purpose and operating principle
- The vessel absorbs the excess water volume generated during heating, limiting pressure increases in the domestic hot water system and protecting the fittings and safety valve from frequent activation.
- The inside of the tank is divided by a flexible diaphragm into a water section and a gas section; an increase in pressure on the water side compresses the gas cushion and gently equalizes the pressure in the system.
Operating conditions and pressure
- The vessels are designed for pressures of up to 25 bar, which should be treated as a limit value and permissible short-term load; in practice, the system operating pressure and safety valve setting should be significantly lower.
- The tanks are suitable for the typical operating temperature range of domestic hot water systems: from sub-zero installation temperatures to approximately 100 °C, with a permissible short-term increase in the medium temperature to 130 °C, corresponding to the resistance of standard EPDM diaphragms used in this type of equipment.
Construction and design
- IBO ITALY domestic hot water expansion vessels are steel pressure tanks coated with a durable blue paint coating that protects against corrosion under typical operating conditions in indoor installations.
- As standard, they have threaded connections (3/4" or 1") for connection to safety groups or domestic hot water systems, and the replaceable diaphragm is suitable for contact with potable water in accordance with the requirements for potable water expansion vessels.
