2. Baxi AquaHeat HIUs
Inside Baxi AquaHeat Heat Interface Unit HIU

Heat Interface Units

Baxi AquaHeat HIU 

For homes fed with heat from a heat network, the Baxi AquaHeat HI/HWI (Heating Indirect/Hot Water Indirect) is the answer to your apartment’s heating and hot water requirements, and the Baxi AquaHeat HI is perfectly suited to supply heat to communal and commercial premises in your development.

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Features and Benefits

Multiple outputs

Range of heating outputs from 4kW to 60kW and domestic hot water outputs from 18kW to 57kW.

Easy installation

Optional first fix rail with in-built filling loop and stand-off bracket to allow for installation with various primary and tertiary pipework. Pre-wired with heat meter and Mercurius remote monitoring module.

Highly efficient

Ultra-fast acting, fully modulating PICV perfectly matches energy supply to instantaneous demand and high performance insulation providing very low heat losses.

Remote monitoring and control

Mercurius platform for remote commissioning and monitoring to reduce site on time and giving visibility of errors to improve first-time fix rates.

Reliable

Water Regulation Reg4 Approval. BESA 2023 V3 registered. Covered with a 5-year parts and labour warranty.*
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Product Literature

Specification Guides

Specification Guides

Technical Specifications

Technical Specifications

BIM Files

BIM Files

Baxi Aquaheat HIU

Baxi AquaHeat HIU
BIM file

Reports

Reports

TM65

TM65

Baxi AquaHeat HI Heat Interface Unit Dimensions

AquaHeat HI

Dimensions

A: HIU width = 540mm

B: HIU height = 857mm

C: HIU depth = 260mm

D: Side Clearance = 30mm

E: Upper Clearance = 100m

F: Lower Clearance = 100m

G: Front Clearance (in operation) = 200mm

Baxi AquaHeat HI/HWI Heat Interface Unit Dimensions

AquaHeat HI/HWI

Dimensions

A: HIU width = 540mm

B: HIU height = 750mm

C: HIU depth = 260mm

D: Side Clearance = 30mm

E: Upper Clearance = 100m

F: Lower Clearance = 100m

G: Front Clearance (in operation) = 200mm

Technical Specification

Product ModelHI/HWI - 4/50HI/HWI - 4/50 HI/HWI - 14/50 HI/HWI - 14/50 HI - 50HI - 50
with Heat Meter & Mercurius with Heat Meter & Mercurius with Heat Meter & Mercurius
Product Code786747078674727867476786747778674747867475
Net Weight (Dry) (kg)2726.52726.73030
Net Weight (Wet) (kg)27.52727.527.231.531.5
Gross Weight (packaged) (kg)2726.52726.73030
Height (packaged) (mm)750750750750857857
Width (packaged) (mm)540540540540540540
Depth (packaged) (mm)260260260260260260
Heat Loss in keep warm mode high temp (DH 70°C) (kWh / 24h)0.950.950.950.95--
Heat Loss in keep warm mode low temp (DH 55°C) (kWh / 24h)0.910.910.910.91
Primary Side
Max operating pressure (bar)161616161616
Max operating temperature (˚C)909090909090
Maximum primary flow rate (DHW mode) (55 primary / 50 dhw (m3/h)0.90.90.90.9--
Maximum primary flow rate (space heating mode) (55 primary / 45/35 CH) (m3/h)0.260.260.60.633
Maximum primary pressure differential (kPa)600600600600
Min primary pressure drop req. at Maximum primary flow rate (DHW Mode) (kPa)16161616--
Space Heating hydraulics
Max operating pressure (bar)2.52.52.52.533
Max operating temperature (˚C)858585858585
Safety relief valve setting (bar)333333
Heating temperature setpoint (min - max) (˚C)15 - 8515 - 8515 - 8515 - 8515 - 8515 - 85
Heating temperature setpoint (default) (˚C)454545454545
Heating nominal pump head (kPa)70707070--
DHW hydraulics
Max operating pressure (bar)10101010--
Min cold water supply pressure (bar)1111--
Hot water temperature setpoint (min-max) (˚C)40-6540-6540-6540-65--
Hot water temperature setting (default) (˚C)50505050--
Electrical
Power supply (V / Hz)230V ~50 Hz230V ~50 Hz230V ~50 Hz230V ~50 Hz230V ~50 Hz230V ~50 Hz
Permanent live required (yes/no)yesyesyesyesyesyes
Power consumption (max space heating output) (W)656565651212
Power consumption (standby) (W)333333
Power consumption (max space heating output, with Mercurius) (W)757575752222
Power consumption (standby, with Mercurius) (W)131313131313
Minimum external fuse rating (A)555555
Internal fuse rating (A)555555
Connection Types / Sizes
Primary network flow3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male1 female1 female
Primary network return3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male1 female1 female
Space heating flow3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male1 female1 female
Space heating return3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male1 female1 female
Cold water feed3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male1 female1 female
Domestic hot water flow3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male3/4 ISO G 228 male1 female1 female
Space heating safety valve discharge (mm)151515151212

AquaHeat HIU FAQ's

Heat Interface Unit (HIU) efficiency 

Using a twin plate HIU (indirect Heating & Domestic Hot Water) as an example, there are a few ways in which product efficiency can be measured. Read more..

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Heat Interface Unit (HIU) pros and cons

Find out the pros and cons of Heat Interface Units (HIUs) here at Baxi FAQs...

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How to reset pressure on my Heat Interface Unit (HIU)? 

Watch this video to find out how to reset pressure on my Heat Interface Unit (HIU)...

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What is the price of a HIU (Heat Interface Unit)?

Average cost for a Heat Interface Unit (HIU) can be from around £800 to £1500, depending on the HIU type, performance of the unit and equipment provided.

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What support is available in the design of my system?

Our Application Engineers can assist in advising clearances, dimensions, and possible locations for consideration. Find out more...

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Contact your TSM

Our Technical Sales Managers will ensure you get the heating solution that’s right for your project.

Get in touch

Integrated Solutions Brochure

We’re rising to the challenge by streamlining our processes, investing in energy-saving technologies and creating some of the most efficient heating and hot water solutions on the UK & Ireland market.

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Baxi Technology and Innovation

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Baxi and its associated brands offer a broad range of low carbon and highly efficient heating and hot water solutions for both new build and retrofit commercial applications.

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Knowledge Centre

Relevant and informative content on a range of topics and key challenges.

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Commercial Brochure

Together with specifiers, contractors, wholesalers and commercial end-users, we put in place the most suitable products from our vast portfolio, to make sure we deliver the right solution, every time.

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*when evidence of commissioning supplied