IBO ITALY domestic hot water expansion vessels are diaphragm pressure vessels used in domestic hot water systems to stabilize pressure and compensate for the thermal expansion of water. They have a blue exterior coating and are designed for operation in closed water systems within a temperature range of approximately -10 to 100 °C (briefly up to 130 °C, for a maximum of 2 hours).
Purpose and operating principle
- The vessel absorbs the excess volume of water produced during heating, limiting pressure increases in the domestic hot water system and protecting fittings and the safety valve from frequent activation.
- The inside of the tank is divided by a flexible diaphragm into water and gas sections; an increase in water-side pressure compresses the gas cushion and gently equalizes pressure in the system.
Operating conditions and pressure
- The vessels are designed for pressures of up to 25 bar, which should be treated as the limit value—a permissible temporary load; in practice, the system operating pressure and the 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 brief 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 finish 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 diaphragm vessels used with drinking water.
