Expansion vessel Cimm ERE CE 35cp L 820035/002

Product detailed description

Expansion vessels are essential components in closed heating systems where thermal expansion of water must be accommodated safely. This vessel is commonly used in residential and commercial buildings with hydronic heating systems. Installers typically integrate these vessels into systems to prevent overpressure caused by temperature fluctuations. The device helps maintain stable pressure levels and protects the system from mechanical stress.

In installations involving radiators, underfloor heating or heat pumps, the expansion vessel prevents damage to pipes, valves and pumps. It is often mounted near the boiler or circulation pump, depending on the system layout. The vessel’s internal diaphragm separates the air chamber from the water side, allowing controlled expansion while maintaining pre-charge pressure. Proper sizing ensures the vessel can handle the system’s maximum thermal expansion volume.

Technical parameters

Installation and connection

The vessel should be installed in a location accessible for inspection and maintenance. Ensure the vessel is mounted vertically with the connection facing downward to allow proper drainage. Connect using a M 3/4 inch G thread to the system’s expansion line. Before tightening, apply a sealing compound or PTFE tape to the male thread to prevent leaks. Verify that the vessel is pre-charged to the correct pressure level specified by the manufacturer’s instructions.

Common installation errors include incorrect orientation, failure to isolate the vessel during system filling, and neglecting to bleed air from the system after installation. Always check the vessel’s pressure gauge after installation to confirm the pre-charge pressure aligns with the system’s operating pressure. Avoid placing the vessel near sources of direct heat or vibration, which could affect its performance over time.

Compatibility and accessories

This expansion vessel is compatible with standard heating systems using copper or steel pipework. It works well with thermostatic radiators, heat emitters and circulation pumps. To complete the installation, ensure that appropriate isolation valves, pressure gauges and safety relief valves are included in the system design. These accessories help monitor and control system pressure effectively.

Technical background for designers

The expansion vessel operates by compressing the air chamber when water expands due to heating. The diaphragm ensures that water and air remain separated while allowing pressure changes to be absorbed gradually. The vessel’s white polyethylene casing provides resistance to corrosion and chemical exposure, making it suitable for long-term use in closed systems. Its compact dimensions (height 435 mm, diameter 380 mm) make it suitable for tight spaces in mechanical rooms or utility areas.

Designers must consider the system’s total water volume and expected temperature variations when selecting the vessel size. The vessel’s capacity must match the system’s thermal expansion requirements to prevent frequent pressure fluctuations. Proper integration with the system’s safety devices ensures that the vessel performs optimally and extends the lifespan of the entire installation.

Service and operation

Periodic checks of the pre-charge pressure are essential to ensure the vessel continues to function correctly. If the pressure drops below the operating level, it should be recharged using a bicycle pump or air compressor according to the manufacturer’s guidelines. Inspect the vessel’s casing for signs of wear, cracks or discolouration, which could indicate internal damage or exposure to incompatible substances. Always follow the technical data sheet for specific service recommendations.

Frequently asked questions

Can the vessel be used in a closed-loop solar heating system?
Yes, provided the system’s operating pressure and temperature do not exceed the vessel’s specifications of 1.5 bar and -10+100°C.

Is a pressure gauge required for the vessel’s operation?
While not mandatory, a pressure gauge is recommended to monitor the vessel’s pre-charge and system pressure regularly.

Can the vessel be installed horizontally?
No, the vessel must be mounted vertically with the connection facing downward to ensure proper drainage and diaphragm function.

How does the vessel handle thermal expansion in a mixed heating system?
The internal diaphragm adjusts to accommodate both cold and hot water expansion within the specified temperature range of -10 to +100°C.

Documents for download

• Documentation for downloading (PDF)
• Documentation for downloading (PDF)
• Documentation for downloading (PDF)