Expansion vessel for domestic hot water CIMM ACS 08 L, capacity 8 L, pressure 2.5/10 bar, temperature -10 to +100 °C

The CIMM ACS 08 L is a diaphragm expansion vessel designed for domestic hot water systems with an 8 litre capacity. It is intended to absorb the thermal expansion of water in closed hot-water circuits, maintaining stable pressure levels and protecting piping, valves and fixtures. The vessel operates across a wide temperature range and is suitable for typical residential and light-commercial installations where a compact expansion solution is required.

Advantages

The diaphragm design separates the water from the gas cushion, reducing the risk of corrosion and ensuring consistent pressure response over repeated thermal cycles. Its 8 L capacity provides a balance between compact size and useful expansion volume for small to medium hot water circuits. Rated for operation at elevated temperatures, the vessel supports systems that experience a wide range of water temperatures while helping reduce pump cycling and minimize pressure fluctuations.

Suitable for

• Domestic hot water (c.w.u.) systems in single-family homes
• Small apartments and flats
• Light-commercial installations with limited hot-water circuits
• Systems requiring protection against overpressure and frequent pump cycling

Key specifications

• Capacity: 8 litres
• Working pressure range: up to 10 bar, with a notable intermediate rating at 2.5 bar for typical pre-charge conditions
• Operating temperature range: -10 °C to +100 °C
• Diaphragm-type internal separation between water and gas cushion
• Compact cylindrical design suitable for wall-mounted or floor-standing installations depending on fittings

How to use

Install the expansion vessel into the closed hot-water circuit at a location recommended by the system designer or installer, typically near the boiler, hot-water storage tank or circulation pump. Ensure correct orientation and secure mounting according to local codes and manufacturer installation instructions. Pre-charge the gas side to the specified system pressure before final connection, then connect to the system and check for leaks. Regularly inspect pre-charge pressure and diaphragm condition as part of routine maintenance to ensure continued performance.

Usage recommendations

Verify that the vessel pre-charge matches the static pressure of your system and that the selected capacity suits the expansion volume of your installation. For systems operating near the upper temperature limits, ensure surrounding components and fittings are rated accordingly. Schedule periodic inspections of pressure and diaphragm integrity to maintain reliable operation and prevent service interruptions.