Expansion Vessel Reflex DE 25L 7304013 for Domestic Hot Water (DHW)

The Reflex DE 25L expansion vessel for Domestic Hot Water (DHW) is a 25‑litre diaphragm vessel engineered to absorb pressure fluctuations in residential hot water circuits. It accommodates thermal expansion, reduces short cycling of pumps and valves, and helps maintain stable system pressure for reliable operation of piping and appliances. The vessel is suitable for use in closed domestic hot water systems where temperature changes cause volume and pressure variations.

Advantages

The diaphragm design separates the water and gas sides to ensure consistent pressure control and minimize maintenance. With a 25‑litre capacity, the vessel balances small to medium sized domestic systems, reducing mechanical stress on pumps and valves. Its compact build allows flexible placement near water heaters, boilers or circulation loops to improve system stability and extend component life.

Suitable for

• Residential domestic hot water systems
• Hot water circulation loops and storage tanks
• Systems requiring reduction of pump and valve cycling
• Installations where thermal expansion protection is needed

Key specifications

• Diaphragm type expansion vessel with separated water and gas chambers
• Nominal volume: 25 litres
• Intended application: domestic hot water (DHW) systems
• Materials suitable for potable hot water contact (diaphragm and vessel body)
• Compact footprint for installation near heaters or circulation lines
• Pre-charged gas side to compensate thermal expansion and stabilize pressure

How to use

Install the expansion vessel on the return or supply pipe of the domestic hot water circuit, close to the heat source or circulation pump, following local plumbing codes and manufacturer mounting recommendations. Ensure the vessel is mounted in a position that allows safe access to the gas valve for pressure checks. Set the pre-charge pressure to match the static system pressure before filling the system with water, then vent and pressurize the circuit. Regularly check the gas pre-charge and inspect connections for leaks during routine maintenance.

Usage recommendations

Confirm the system’s maximum working pressure and static pressure, and adjust the vessel pre-charge accordingly. Use a pressure gauge and a suitable pump to set and verify pre-charge. Schedule periodic inspections of the diaphragm vessel and fittings as part of normal system maintenance to ensure continued protection against thermal expansion and pressure fluctuations.