75 Indirect

Logic Heat Interface Units (HIU) Indirect - 75 Indirect

The Ideal Heat Interface Units (HIU) are heat energy transfer units, designed for use in conjunction with centralised boilers, district heating or central energy systems. The function is to efficiently transfer heat from
the plant room to the individual dwellings central heating (CH) and domestic hot water (DHW) systems.

The Logic Indirect HIUs are the latest 'intelligent’ range of HIU from Ideal. The Logic HIU is the complete solution for instantaneous hot water production and space heating control. The indirect wall mounted HIU,
providing instantaneous priority direct hot water (DHW) and modulated central heating (CH). This can be converted to under floor heating including inbuilt safety thermostat capability.

Ideal Logic Indirect Heat Interface Unit front


  • 2 year parts and labour warranty
  • All the Logic HIUs incorporate a spacer piece which can be easily removed and a heat meter fitted inside the unit. This allows the energy used by each individual apartment to be recorded and charged accordingly
  • Twin plate design hydraulically separates both domestic and space heating from the central primary supply
  • Pump bypass protection, in case of complete radiator TRV shutdown
  • Compact and lightweight
  • Fully insulated EPP front cover
  • Convertible to underfloor heating
  • Ability to pre-heating of the DHW exchanger
  • Compact Wall Hung
    Compact Wall Hung
  • 2 Year Warranty
    2 Year Warranty
  • Erp Prepared
    Erp Prepared


Logic Heat Interface Units (HIU) Indirect 75 Indirect

Height630 mm
Width550 mm
Depth265 mm
Heating Set Point25 to 75°C
Nom. heating exhangner net output15 kW
Secondary circuit (Max pressure rating)3 bar
Secondary circuit (Max operating pressure)2.5 bar
Pump UPSUPS 15/60
Pump bypass setting0.45 bar
Pressure switch opening0.4 bar
Pressure switch closing0.8 bar
Safety relief valve setting3 bar
Safety thermostat55˚C ±3°C ±3
Expansion vessel7.5 litre
Under floor heating capabilityOptional
Heating control cicuitVOLT FREE
Maximum working pressure (primary)16 bar
Maximum working pressure (secondary)3 bar
Maximum temperature85°C
Max. percentage of glycol30%
Max. recommended primary cicuit flow rate1.2 m³/h
Min. differential pressure on domestic water modulating valve^p 0.35 bar
Set Point DHW temperature42 to 60°C
Max. Domestic hot water pressure10 bar
DHW cicuit max. flow rate18 l/m
Min. flow rate to activate domestic flow sensor2.7 l/m
Max. Differential pressure on domestic water modulating valve1.65 bar
Nom. DHW heat exchanger net output75 kW
Power supply230 V (ac)±10% 50Hz
Max power consumption105 W
Protection classIP 40
Actuatorstepper 24 V
ProbesNTC 10 kΩ
FrameRAL 9010 sprayed steel
Protective shell coverEPP (Expanded polypropylene)
Componentsbrass BS EN 12165 CW617N
Pipesstainless steel
Exchangerbrazed stainless steel

Standard and Optional kits


  • CF ECHO II ultrasonic meter
  • CF ULTRAMAXX V ultrasonic meter
  • Flushing Bypass


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Brochures Expand/Close
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HIU Product Guide 2017
Technical Information
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211347 HIU 50 Indirect Spec Sheet.pdf
211348 HIU 75 Indirect Spec Sheet.pdf
BIM components
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BIM files available for this product - Please click here to download.
Installation and user guides
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HIU installation and servicing manual.pdf
Logic HIU Installation & Servicing 211203-4.pdf

Other Logic Heat Interface Units (HIU) Indirect models available