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Unrivalled performance Our pioneering technology and control systems deliver high precision heat management and unrivalled performance in both domestic and district heating environments.

Best for through-life costs Intelligent design leads to greater simplicity – that’s why our systems are cost effective to install, more reliable and cheaper to run and operate.

Better by design Our unique and innovative technology has been refined over many years and is protected by numerous patents relating to water storage, heat exchange and the networking of communal heating systems.

The SLIM Extra HIU is based on the SLIM HIU, however this unit is fitted with an additional combined automatic balancing and control valve, with pipework to connect directly to the central heating system.  The HIU is fitted with a tamperproof steel casing, ideal for less secure environments.


HIU Type Heating and Hot Water
Hot Water Configuration Indirect
Heating Configuration Direct
Heating Temperature Control No
Built-in Heat Meter Yes
Dimensions – HIU Case (mm) 552 (W) x 654 (H) x 132 (D)
Dimensions – inc. Valves (mm) 552 (W) x 754 (H) x 156 (D)
Heating Output (nominal) 40kW
Hot Water Output (nominal) 65kW


As standard the HIU controller can accept a switched live signal from the apartment heating controls and is equipped with a wiring centre for all electrical connections including the heat meter MBus connections. A number of optional extras are available, as shown below.


  • Decorative white steel casing wrap
  • Pre-plumbing jig
  • Various heat meter models
  • Landlord security Isolation
  • DHW recirculation pump kit (for mounting external to casing)
  • Water hammer arrestor
  • ModBus communication module
  • SLIM Plus – 80kW DHW output


SLIM Extra Datasheet   SLIM Extra Installation Instructions


Technical Detail

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