Expansion Vessel 24 CMR-8 3/4" DHW

The Ibaiondo 24 CMR expansion vessel, reference 01025082, is a 24-liter diaphragm expansion vessel specifically designed for open domestic hot water (DHW) systems. Its function is to absorb the increase in volume that water undergoes when heated, helping to control pressure fluctuations in the installation and protect its components.

This model operates at a maximum working pressure of 8 bar, is supplied with a factory air precharge of 3 bar, and features a 3/4" threaded water connection. Unlike lower-capacity CMR models, the 24 CMR incorporates a stainless steel bolted cover and a replaceable membrane suitable for potable water.

24-liter expansion vessel for DHW

The Ibaiondo 24 CMR is designed for open-circuit domestic hot water installations. When the water temperature rises, its volume also increases. The vessel absorbs part of that expansion and compresses the air contained in its chamber, reducing the pressure increase that would occur in an installation without an expansion vessel.

When the temperature drops, the pressure stored in the air chamber helps return the water to the circuit, compensating for the volume variations inherent to system operation.

24-liter capacity

The vessel’s nominal capacity is 24 liters. Correct sizing of the expansion vessel must take into account the total water volume of the installation, the supply pressure, the safety valve set pressure, and the operating temperatures.

Proper selection helps keep pressures within the intended limits and reduces unnecessary operation of the safety valve.

Maximum working pressure of 8 bar

The 24 CMR model has a maximum working pressure of 8 bar. Ibaiondo expressly states this value for reference 01025082, distinguishing it from other smaller footless CMR vessels that may operate at 10 bar.

The operating pressure of the installation must never exceed the maximum pressure indicated on the vessel nameplate.

Factory precharge of 3 bar

The vessel is supplied from the factory with an air precharge of 3 bar. This pressure may need to be adjusted during commissioning to suit the actual conditions of the installation.

Checking and modifying the precharge must be carried out with the vessel properly isolated and with no water pressure on the membrane, following Ibaiondo’s installation and maintenance instructions.

Replaceable membrane suitable for potable water

Ibaiondo’s current technical documentation states that the 24 CMR PN8 model is an exception within the footless CMR range: it incorporates a replaceable membrane in accordance with EN 13831 and suitable for contact with potable water.

This design makes it possible to replace the membrane when necessary, avoiding the need to replace the entire vessel due to wear of this component.

Bolted cover and stainless steel connection

The 24 CMR incorporates a stainless steel bolted cover associated with its replaceable membrane system. Ibaiondo also specifies a stainless steel water connection for this model.

The hydraulic connection is R 3/4" male gas threaded, suitable for integration into compatible DHW installations.

System temperature from -10 to +100 °C

The current technical sheet specifies a system temperature range from -10 to +100 °C. The vessel must be installed and used within these limits and in accordance with the manufacturer’s conditions.

Steel construction and white finish

The tank is made of steel and has a white painted exterior finish. The structure is designed to withstand the working pressures expected in domestic hot water installations.

The vessel also includes a charging valve that allows the air chamber pressure to be checked and adjusted during installation and maintenance operations.

Compact dimensions

The Ibaiondo 24 CMR has a diameter of 320 mm and a height of 430 mm. Its approximate weight is 4.5 kg.

It is a footless model, so it must be installed in accordance with the manufacturer’s mounting instructions and, where appropriate, using the proper support elements.

Helps reduce safety valve discharges

A correctly sized vessel absorbs the thermal expansion of the water and prevents the increase in volume from translating directly into an excessive rise in pressure.

This helps reduce safety valve openings and drips caused by water expansion during heating cycles, also reducing unnecessary water loss.

Helps dampen pressure variations

The air chamber and membrane help dampen pressure variations produced during circuit operation. Ibaiondo also notes that incorporating a CMR vessel can help reduce the effects of water hammer associated with sudden flow changes.

Installation in domestic hot water systems

The 24 CMR is intended for DHW installations where it is necessary to compensate for the thermal expansion of water, such as installations associated with storage tanks, water heaters, hot water production systems, and other compatible sanitary circuits.

The vessel must be selected according to the actual hydraulic parameters of each installation and installed so that it can be properly inspected and maintained.

Precharge maintenance

The precharge pressure should be checked periodically to maintain proper vessel operation. Ibaiondo recommends checking it with the vessel hydraulically isolated and drained of water, avoiding measurements with water pressure acting on the membrane.

Any work on the vessel must always be carried out with the installation depressurized and by qualified personnel.

Technical features of the Ibaiondo 24 CMR

• Brand: Ibaiondo.
• Reference: 01025082.
• Model: 24 CMR.
• Series: CMR DHW.
• Type: diaphragm expansion vessel.
• Application: open domestic hot water systems.
• Capacity: 24 liters.
• Maximum working pressure: 8 bar.
• Factory precharge: 3 bar.
• Precharge gas: air.
• System temperature: -10 to +100 °C.
• Membrane: replaceable.
• Potable water membrane: yes.
• Membrane standard: EN 13831.
• Cover: stainless steel bolted.
• Water connection: stainless steel.
• Connection thread: R 3/4" male gas.
• Tank material: steel.
• Charging valve: included.
• Exterior finish: white paint.
• Diameter: 320 mm.
• Height: 430 mm.
• Weight: approximately 4.5 kg.
• Configuration: footless model.
• Manufacture: in accordance with Pressure Equipment Directive 2014/68/EU.
• Warranty indicated in the current technical sheet: 3 years.

Compact expansion vessel for DHW installations

The Ibaiondo 24 CMR combines a 24-liter capacity, 8 bar maximum pressure, and 3 bar precharge in a compact Ø320 x 430 mm format. Its replaceable membrane suitable for potable water and stainless steel connection set it apart from lower-volume CMR models in the same family.

It is especially suitable for controlling thermal expansion of water in DHW installations, helping stabilize circuit pressure, reduce safety valve discharges, and protect installation components against pressure variations.

Important: the factory precharge of 3 bar must be checked and, when necessary, adjusted to the actual conditions of the installation. Sizing, installation, and maintenance must be carried out in compliance with Ibaiondo instructions and applicable regulations.