Galmet bi-valent domestic hot water cylinder with two spiral coils for solar collectors and central heating 200 L

The Galmet bi-valent domestic hot water cylinder with two spiral coils, 200 L, is a storage tank engineered for combined use with solar thermal collectors and a central heating system. The cylinder stores domestic hot water and features two separate spiral heat exchangers: one coil dedicated to solar collector input and another for boiler or central heating system exchange. This arrangement allows independent heat sources to operate without direct mixing, improving system flexibility and enabling efficient transfer of thermal energy into the stored potable water volume.

Advantages

The dual-spiral design separates solar and central heating circuits, reducing hydraulic interference and simplifying control strategies. A 200-litre capacity meets typical residential hot water demands while maintaining compact dimensions for basement or utility-room installation. The internal heat exchangers are designed to provide effective heat transfer from low-temperature solar collectors as well as from higher-temperature boiler circuits. Construction materials and surface treatments are selected to resist corrosion and scale formation under normal domestic water conditions.

Suitable for

• Residential systems combining solar thermal collectors with a gas, oil or electric boiler
• Homes requiring a dedicated domestic hot water tank decoupled from heating circuits
• Retrofit projects where existing central heating is combined with new solar panels
• Installations needing reliable DHW storage with stratified heat input from two sources

Key specifications

• Nominal volume: 200 litres of domestic hot water storage
• Two internal spiral heat exchangers for independent heat sources
• Designed for connection to solar thermal collectors and central heating circuits
• Vertical cylinder configuration suitable for indoor installation
• Materials and surface treatment engineered for potable water compatibility and reduced corrosion

How to use

Connect the lower or designated solar coil to the solar loop and the second coil to the boiler or central heating return as specified in the system design. Ensure proper integration with temperature sensors, mixing valves, and safety devices according to local regulations and manufacturer instructions. Commission the system by flushing circuits, checking for leaks, and verifying that pumps and controls activate the appropriate heat source depending on available solar output and boiler demand. Regularly check anode condition and perform scheduled maintenance to preserve heat transfer efficiency and water quality.

Usage recommendations

For optimal performance, configure control logic to prioritise solar heat when collector temperatures exceed the tank setpoint and allow the boiler coil to provide backup heat during low solar yield. Install appropriate expansion vessels, pressure relief valves and non-return valves. Follow local plumbing codes and have the unit installed by a qualified heating professional to ensure safe and efficient operation.