Vital Energi are the sole suppliers of KVM manufactured hydraulic interface units (HIUs) in the UK.

Designed and developed with the benefit of our experience of CHP/community energy systems, these units, branded the Vital Aqua Varm, enable the householder to enjoy hot water and central heating - instantly and on demand.

For the ultimate in bespoke solutions, the design of each HIU is considered on a project-by-project basis, and is manufactured according to the unique requirements of each client.

HIUs were first developed in Denmark during the 1970s, prompted by campaigns to reduce the amount of water used domestically. The Aqua Varm is based on these designs but has been adapted and re-engineered to suit the unique conditions of the UK market, such as water quality, water pressure and levels of demand.

Sometimes referred to as a heat board or a customer interface unit, an HIU is a control station within a residential or commercial unit. It works as the heat exchanger interface point between the community heating network and the internal heating/domestic hot water systems. The units can also be fitted with a heat meter, enabling dwellings to be individually metered and billed for their energy consumption.

Within the HIU, the control components serving the hot water and central heating systems gives increased control over when and how much hot water can be used. The Vital Energi range of HIU's are available as part of Vital's contracting installation or on a supply-only basis. Each unit bears the CE mark of approval

For more information on our range of HIU's, click here to download our brochure

Vital Aqua Varm Design Features:

• Compatible for supply from either:
  • a decentralised energy centre within a multi-dwelling development
  • a centralised energy centre serving an extensive community heating network
• They are based on many years experience in district heating and a proven design with in excess of 100,000 units installed across UK and Europe
• Instantaneous domestic hot water with rapid response
• High DHW flow rates, which significantly exceeds NHBC requirements
• Reliable, quality-built components
• Flow rates automatically adjusted via a differential pressure control valve as standard
• Direct or indirect HIU's available
• A factory-fitted heat meter is an optional component

Vital Energi specify three different type of HIUs which all share several key standard features:

• CE marked guaranteeing the product meets the requirements of the applicable European directive(s)
• All pipework is made of stainless steel
• Plate heat exchangers made of stainless steel
• Differential pressure control
• Efficient heat transfer
• Facility for high-accuracy ultrasonic heat meter, which can be factory-fitted
• DN 20 Ball valves on all primary and secondary connections to the HIU
• Strainer/s and drain cock
• Steel 'lift-off' casing finished in white (other options on request)
• Casing can be removed for ease of maintenance
• All components securely fixed on to a galvanised steel frame
• Design allows adequate access for commissioning and for future component replacement pressure tested to 15 bar g after assembly
• Maximum working pressure of 10 bar g
• Quiet operation of components
• Tested prior to despatch
• Supplied fully assembled

• Vital Aqua Varm Indirect Heating
• Vital Aqua Varm Direct Heating
• Vital Aqua Hot Water Only